In the latter decades of the second century B.C., China consciously entered into regular contact with the other civilizations of Eurasia. Organized trade routes, both by land and by sea, soon linked the four great cultures of the continent [Chinese, Indian, Middle Eastern, and Roman]. In addition, Eurasia's central sea of grass provided a third linkage, more sensitive to military than to mercantile enterprise. . . . Thus, the Eurasian ecumene was closed as never before.

This event may be compared with the far more famous closure of the global ecumene in the sixteenth to eighteenth centuries A.D., when European explorers, merchants, and missionaries systematically opened up (he coasts and islands of all the world to Western enterprise (McNeill 1963, 297).

"William H. McNeill's comment highlights a major structural event in the process by which several largely separate world-systems in Afroeurasia became linked into a single interactive system in a series of waves of integration and disintegration between 500 B.C.E. and 1400 C.E. This Afroeurasian system first emerged with trade connections between China and Rome some 2,200 years ago. It expanded, contracted, and nearly decoupled in a series of oscillations for over two millennia. It became united most fully under Chinggis Khan (formerly spelled Genghis) in the thirteenth century, only to decouple again under early Ming rule in China (early fifteenth century). Throughout these changes South and Southeast Asia remained transit grounds whose dynamics were less tightly coupled to the emerging Afroeurasian world-system, but they nevertheless played an important role. Out of the ashes of the collapsed Mongol Empire the northwestern European periphery, following the pattern of semiperipheral development, transformed into a new type of intensely capitalist regional system that eventually came to dominate the older core regions and to incorporate the rest of the globe.

In "this chapter we examine some of the complex history of the emerging Afroeurasian world-system. Before embarking on our historical explorations, however, it would be useful to review the major theoretical issues we will be addressing through this exploration.

The new connections among the various previously autonomous world-systems that came to form the Afroeurasian world-system raise once again issues of (l) continuity versus transformation; (2) the nature of world-system boundaries; (3) the processes of mergers and the incorporation of states and nonstate societies; and (4) the role of semiperipheral areas in hierarchy formation and systemic transformation.

We argue that before the first opening of the Silk Road there were at least three major state-based world-systems on the Eurasian landmass: the Chinese, the South Asian, and the West Asian. These three core regions became involved in long processes of mutual incorporation that was uneven and sporadic, with periods of increasing and decreasing incorporation. At times they joined to form a single system constituted by the equal exchange of luxury goods and bullion among the three main core regions (Amin 1991). This system was tightly linked between 200 B.C.E. and 200 C.E., 500 and 900 C.E., and 1200 to 1400 .C.E. At other times the system decoupled into largely autonomous smaller world-systems, but after each successive decoupling the separated regions were increasingly transformed by their interactions with the larger whole. What occurred was the merging of the largest networks, the information and the prestige-goods nets while the political/military and bulk-goods nets remain distinct (except under the Mongols, when the military/political net also merged briefly).

Whether or not the formation of the Afroeurasian world-system constitutes a unique - or merely a rare - form of incorporation, it is clear that the constituent core regions and the new larger system incorporated several smaller world-systems -notably in West Africa and Southeast Asia. This process of incorporation of previously autonomous systems unleashed significant changes within the newly incorporated regions.

As we have seen in the previous chapters, more complexly organized societies transformed their less complex neighbors. This often occurred through the incorporation of a less complex society into a more complex core/periphery hierarchy. During these two millennia the incorporation and transformation of nonstate societies increased dramatically. What remains less clear is whether the processes of incorporation were themselves transformed, or if only the relative density of different degrees of incorporation changed.

The problematic roles of pastoralists also suggest new processes of incorporation and core/periphery hierarchy formation. As we will see, some of the most dramatic changes to occur in these two millennia were due to the nomadic pasroralists of Central Asia (Barfield 1989; Frank 1992). These nomads had a much larger effect on the core/periphery hierarchies into which they were incorporated than did nomadic foragers, sedentary foragers, or sedentary honiculturalists. The most dramatic example of this, of course, was the Mongol conquest of much of Eurasia in the thirteenth century.

The most difficult and problematic era of world-system history is the history of the Eurasian landmass and the shifting, pulsing variation in prestige-goods trade, political-military interactions, bulk-goods trade, and information exchange networks. The available histories of the states, empires, and nonstate societies occupying this region are more than any one scholar can master in a lifetime. Nevertheless, we will try to draw a systematic account from those materials that we have examined. The first problem to consider is how to periodize this history.

Jerry Bentley (1993) divides the past two millennia into four eras. First is the era of the ancient Silk Roads, from about 200 B.C.E. to about 400 C.E. It is notable that the Roman and Han Empires rose and fell in tandem. Virulent diseases communicated along the Silk Road seem to have played a major role in the ending of this era. The second era runs from the seventh through tenth century. In this era sea lanes were opened and the volume of traffic increased significantly.

Many historians see a major shift occurring around 1000 C.E. (McNeill 1963, 1982; Bentley 1993; Beckwith 1987b; Abu-Lughod 1989; Bardett 1993). Still, in some areas the second phase blends into the third era from approximately 1000 to 1350 C.E. Trade again increased on both land and sea, but more dramatic was the rise of steppe nomad empires, especially the Mongol Empire in the thirteenth century. This is also the era in which Europe was "made," as Robert Bardett (1993) so aptly phrases it. Finally, after a century or more of demographic recovery the modern European era of expansion began in the late fifteenth century. These eras are not discrete, nor are they geographically uniform, but rather segue into each other and vary spatially (see Figure 8.1).

The second major problem is how to organize the discussion of the various states and empires of Eurasia. We follow McNeill's (1963) lead in moving from east to west: the Chinese Empire, South Asian states (India), and then the West Asian and Mediterranean states. Regarding the West Asian and Mediterranean core region we will adapt David Wilkinson's (1987a, 1987b) terminology and refer to this as the "Central System." We also adapt Wilkinson's terms for the China-centered and Ganges-centered regions - Far Eastern and Indie world-systems. Rome had been a periphery of the Central System but became part of the core of the system during the first phase of this era. Because history never just begins at a point in time, we sketch some of the major structural events that occurred before our first phase to give some sense of historical continuities. Though the geographic divisions are conventional, they denote real divisions, albeit divisions that shift and blur through time (see Map 8.1).

In this period both the Roman Empire (Dyson 1985; Mattingly 1992; Wells 1992; Whinaker 1994) and the Han Dynasty (Latrimore 1940; Barfield 1989, 1990; Fried 1952) began to expand outward, seeking outlets for products and sources of scarce materials. Central Asian nomadi played a crucial role in opening and maintaining this trade (Barfield 1989; Frank 1992; Hodgson 1974a, 1974b; Teggart 1939; McNeill 1963). In world-system terms, three relatively isolated world-svstems mereed at the level of the prestige-goods net. Ideas, products, and people moved along the Silk Roads. The roads over the Hindu Kush and along the Indian Ocean littoral also drew the South Asian world-system into this newly merging larger world-system, although not as tightly. Though this was not the first contact between the two world-systems at opposite ends of the Eurasian land-mass, it was the first instance of sustained trade. Direct trade between China and Rome, in the sense of Roman or Chinese merchants carrying goods the entire distance, did not occur. Still, the links in the chain of down-the-line trade became fewer and longer and the volume and velocity of trade reached levels higher than ever before.

During the last six centuries B.C.E. major changes took place throughout Eurasia. In the east, growing from the early Shang Dynasty (1520-1027 B.C.E.), a state-based world-system developed in what we now know as China during the first millennium B.C.E. It was marked by several centuries of warfare, the so-called Warring States period (403-221 B.C.E.), and finally was united into a corewide empire in 221 B.C.E. by Shih HuangTi in the Ch'in dynasty (221-206 B.C.E.). This short-lived empire was replaced by two succeeding Han dynasties (201 B.C.E.-9 C.E.; 24-220 C.E.). The region was not united again until the rise of the Sui dynasty in the 590s C.E. During this time the extent of sinicized territory expanded greatly from its Yellow River homeland to include a much larger territory, approximately the size of modern China, plus a tongue of territory extending into the Tarim Basin (see Map 8.2).

In the early part of this era control by a growing Chinese landlord class was more easily accomplished than in the Central and Indie systems because it was more difficult for peasants to escape to adjacent territory suitable for farming. This circumscription factor led to relatively early and stable empire formation in China. Also during this time a uniquely Chinese linkage between military, religious, and familial leadership developed in association with the keeping of written records. The classwide literacy of the Mandarins is the main reason that so much more is known about early China than about many other early states.

During the Warring States period the old landed nobility was supplanted by a "gentry" that did not necessarily have a hereditary claim on land and peasants but that nevertheless controlled them. The rise of the gentry was accompanied by an increasingly elaborate bureaucratic machinery for administering the state. This social order persisted for the next two millennia with only relatively minor changes.

Much less is known about South Asia. This is due in part to the persistence of oral tradition until quite late as well as a primary focus on religious and philosophical, as opposed to political and economic, topics in oral and written literature. Geographic features contributed to Indie isolation. Surrounded by mountains, jungles, and ocean. South Asia may have been invaded less often than other regions. Invaders, such as the Aryans and Alexander the Great, typically came from the northwest. Consequently, there was less external pressure to unite in order to amass large armies for defense.

Many centuries after the so-called Aryan invasion of the Ganges Valley (around 800 B.C.E.) local states began to develop in what is now northwest India. During this time the caste divisions developed, as did Buddhism andJainism. Not until 321 B.C.E., when Mauryan rule was established in the wake of Alexanders invasion (327-325 B.C.E.), did anything approximating a corewide empire develop. Even Mauryan rule did not unite all of India, however; this was not achieved until the British conquest.

The Mauryan Empire collapsed late in the second century B.C.E. Smaller warring states dominated the region until Gupta reunification in 320 C.E. From the time of the Mauryan Empire, Indian traders, travelers, and monks made numerous contacts with Southeast Asian states and with Central Asia. The most notable aspects of these contacts were trade and the spread of Buddhism (Bentley 1993; Beckwith 1987a, 1987b, 1987c). It is interesting to note that this empire flourished at the same time that both China and Rome were divided into numerous warring states. Indian merchants in Southeast Asia brought the Hindu idea of divine kingship as well as prestige goods, and these influences led to local state formation (Wheatley 1975).

In the West Asian (Central) system the older Mesopotamian and Egyptian core regions had become linked, first by trade but later, around 1500 B.C.E., into a single PMN. This core region was interacting by means of trade with much of Europe and the Indus River valley during the Bronze Age, but the Indie and Central PMNs were not yet linked into a single sustained interaction system of allying and conflicting states. The rise of large empires, especially the Assyrian and Persian (Achaemenid) Empires, brought most of the core region into a single corewide state. These early states were not "marketless," as Karl Polanyi (1957a) claims. Merchants sometimes operated on their own account rather than being agents of states, and interest was charged on loans in Siimerian city-states, the earliest of early states. But the relative importance ofcommodified production and exchange in these states was still quite low in comparison with later commercialized empires.

Already in the Mesopotamian and Egyptian world-systems the phenomenon of autonomous semiperipheral city-states specializing in trade between the larger states and empires had appeared. Dilmun probably played this role in linking Mesopotamia with the Indus River valley, and Byblos carried goods from Egypt to the Levant. The Phoenician cities specialized in naval power and maritime trade to a much greater extent than did the Greek cities. Phoenician cities, like later Italian city-states (especially Venice), had little capacity to produce their own agricultural goods. Rather, they relied on their ability to purchase food in exchange for the goods that they traded. The Phoenician cities also went beyond the merchant role, producing certain manufactured goods for export. These were probably the first states in which capitalists (merchants and producers of manufactures for sale) controlled the state machinery. They played a central role in the promotion of production for exchange in the whole Mediterranean littoral and beyond because they encouraged trade between states and empires and they carried goods to peripheral regions, encouraging producers to sell their surpluses in exchange for imports. This process was a main force behind the long-term secular trend toward commercialization in the tributary world-systems (Sanderson 1994c, 1995c).

Early in the fifth century B.C.E. Greek city-states came into conflict with the Persian Empire. By the late fifth century B.C.E. Greeks, led by the Athenian navy, prevented conquest by the Persians and rivaled the Phoenicians as major traders on the Mediterranean (Thompson 1995). Their success was based in large part on the use of booty to pay otherwise landless and unemployed citizens as oarsmen in their ships.

Early in the fourth century B.C.E. Philip of Macedon (359-336 B.C.E.), by enticing the sons of nobles to his court, was able to curtail incessant internal rivalry and mount a united attack on the Greek city-states. By 338 Philip had conquered Greece. "The political history of the Greek city-states in the fifth and fourth centuries B.C. offers a classic example of how dispersed sovereignty, operating within a balance-of-power system, may evolve through a series of unstable alliances toward the hegemony of a single marchland state" (McNeill 1963, 258). This is the typical semiperipheral marcher stare strategy described in Chapter 5. But Greece was yet only a semiperipheral region in the larger Central System. The conquests by Philip's son, Alexander, Hellenized the whole core and briefly extended the empire all the way to India. The conquest of India was only a temporary linking of the Central and the Indie PMNs. Alexander's empire fell into three, making a Central PMN in which the interstate system was composed of large tributary empires and smaller adjacent states.

The Greeks expanded into the western Mediterranean by founding autonomous colonies, as had the Phoenicians. Earlier migrations from the East had established Etruscan agriculture and cities on the Italian peninsula. Beginning as a local stateless tribe incorporated into the Etruscan and the larger Mediterranean networks (Rostovtzeff 1960), the Romans formed an expansive, loosely federated military alliance that conquered the Italian peninsula. Rome used the same strategy of federation - requiring conquered peoples to support Rome in military actions but allowing them to maintain local customs - to conquer the entire Mediterranean region. This was another famous instance of empire formation by a semiperipheral marcher state.

By the close of the third century B.C.E. Rome had conquered the eastern Mediterranean and defeated Carthaginian (Phoenician) rivals in North Africa. A Carthaginian faction had established a colony in Spain that was pursuing a territorial strategy rather than the more usual Phoenician maritime-trade approach to wealth. Hannibal embarked on a semiperipheral marcher state path that nearly led to the conquest of Rome but for the hesitance of the more traditional faction in Carthage, which failed to resupply him at the crucial moment. The Romans never forgot this close call. They destroyed Carthage and purchased Hannibal's life from the Parthian king who had given him asylum.

Late in the first century B.C.E. Octavian, known as Caesar Augustus, succeeded in converting the far-flung Roman conquests into an integrated empire. Rome eventually dominated trade and one of the two core empires of the Central System, stretching from the Iberian peninsula to the borders of Parthian Empire. The Parthian Empire was also a core state within the PMN of the Central System and hence was not a world-empire in the Wallersteinian sense. Rather, the core had become relatively centralized under the control of two large empires.

The Central PMN had been linked to the Indie PMN by means of prestige-goods trade when Mesopotamia traded with the early states on the Indus River. With the decline of the Indus states, trade declined but was reestablished when states arose in the Ganges Valley. Thus the Central and Indie PMNs were part of a single larger PGN in which the two nonadjacent core regions had engaged in equal exchange of luxury goods probably since about 1800 B.C.E. (Wilkinson 1992, 60). Alexander the Great's conquests (334-323 B.C.E.), had they been sustained, would have combined them at the political/military net level. This trade connection became much stronger as the Roman Empire consolidated its power in the Mediterranean during the second century B.C.E.

The Roman Empire was organized primarily around expansionary conquest and the import of booty and slaves into Rome. But there also developed a significant market sector in which goods, labor (in the form of both slaves and wage workers), property, and wealth were exchanged as commodities. Roman contract law was an important basis for market exchange. Though Rome was a rather highly commercialized system in comparison with earlier empires, accumulation remained predominantly organized through the use of coercive state power, and the dynamics of expansion and contraction were primarily tied to the logic of conquest, taxation, and tribute.

The histories of Rome and China are parallel in many ways: the timing of their respective rises to dominance, the domination by military leaders, constant political intrigues, and frequent bureaucratic corruption. Interestingly, geographical transition zones between areas that supported agriculture capable of producing significant surplus and those only capable of supporting subsistence seem to define frontiers more than do policy, politics, or warfare (Lattimore 1940; Whittaker 1994, 85-86). Finally, the three world-systems each had a nested quality: Trade in prestige or luxury goods and information flows extended beyond military control, which in turn exceeded the range of bulk-goods exchange (see Figure 3.1).

There were even more significant differences. The Roman Empire was much more pluralistic, a feature that stemmed from its federation strategy. The family played a less central role in Rome. Roman agriculture was far less intensive. Most significantly, Rome and China faced very different "barbarians", that is, nonstate foes: Rome's enemies never succeeded in uniting into a single force, whereas China's did regularly - a topic to which we now turn.

In 1939 Frcderick J. Teggart, in his famous book, Rome and China, nre,ued chat the warfare on the eastern borders of the Roman Empire and the western border of China were correlated. He further argued that the mechanism of correlation was the movements of various Central Asia steppe peoples. Though he posited a connection, Teggart did not fully specify its mechanisms. That is the task we approach in this section.

In general. Central Asian nomadic groups have what anthropologists call a segmentary lineage structure (Barfield 1993; Sahlins 1961). The important feature of this social structure is that it allows easy formation of alliances and allows a former enemy to become an ally, often rationalized within a kinship metaphor. This allowed a leader to manipulate the prestige-goods economy to promote wider and wider alliances, thus putting larger and larger armies of allies at his disposal.

The Cimmerians and Scythians, who may well have been the first mounted pastoralists, appeared sometime in the ninth century B.C.E. Chinese accounts of horse-riding nomads first appear sometime in the fourth century B.C.E. The formation of the first large steppe confederacy, the Hsiung-nu, coincided with formation of the Ch'in dynasty in China in the late third century B.C.E. (see Table 8.1). As we will see, this was not fortuitous. It was the first cycle of the simultaneous rise and fall of Chinese dynasties and steppe confederations.

There are several recurrent themes in nomad-sedentary relations in Chinese history and several new interpretations. First, the gradual expansion of sedentary agriculture displaced nomads further into the steppe. This expansion was limited by a combination of agricultural technology and local ecology. Sometimes agriculturists who were near this limit adopted a pastoral way of making a living. At other times pastoralists became sedentary. These contradictory processes created a mixed zone along some parts of the Chinese frontier. Where the vegetative zones were sharp, so was the frontier. The nomad-sedentary distinction was thus fundamentally one of livelihood, not of race or ethnicity. This is an early example of the persistence of a cultural boundary despite continual movement of individuals, families, or groups across it (Barth 1969; Haaland 1969).

Second, there were waves of migrations or invasions moving from east to west across the Eurasian landmass. These were driven by the interaction of geographic and political factors. As McNeill (1982, 17; 1987, 265ff.) points out, there is a gradient in temperature and precipitation from east to west over the Eurasia steppe, with the west having better pasture conditions. However, there is a counterattraction in the east: the Chinese Empire.

Third, since nomads generally produced little of interest or value to agricultural Chinese, they often used threats to induce trade: Trading and raiding were alternative means to the same ends (Jagchid and Symons 1989, chap. 1). Khazanov (1983, 202ff.) points out that there was a distinct asymmetry in the demand for this trade. Nomads, due to their specialization, had a much stronger need for sedentary goods - both agricultural goods and handicrafts - than sedentary peoples had for nomad products. The strongest demand for exchanges with nomads came from a second type of trade, one in which nomads played an intermediary role among sedentary peoples. Still, this asymmetry in demand for trade explains why nomads often forced the issue via raiding.

The Chinese eventually developed a cavalry to fight nomads. Some studies show that raiding correlated with changing conditions of trade and changing state stability (Szynldewicz 1989, 154; Barfield 1989). Chinese officials acquiesced to this trade as a way of controlling nomads. Nomad leaders used prestige goods in addition to basic needs in the nomad political economy to shore up and symbolize their power. These interactions fueled changes both in China and among nomads. In times of state decline, nomadic leaders sometimes served as protectors of beleaguered areas. In times of state ascendance, unified Chinese response promoted wider unity among nomads. Nomads were as often a source of change as receivers of change.

In his insightful history of Central Asia, Thomas Barfield (1989) analyzes the interconnections between the rise and fall of the Chinese Empire and various nomad empires. He documents the intimate connection between Chinese Empire and nomad political organization. A key feature of Barfield's analysis is the distinction between inner- and outer-frontier strategies.

In the outer-frontier strategy a dominant nomad leader used violent attacks to terrify Chinese officials, alternating between war and peace to raise tribute payments and improve terms of trade. He assiduously avoided taking over Chinese territory and the entanglements in Chinese politics that conquest would entail. The inner-frontier strategy sometimes developed when a nomad confederation began to disintegrate. Some contending nomad faction leader, typically of a weaker faction, would seek alliance with some Chinese officials against his nomad rivals. The Chinese officials acquiesced, intending to use "barbarians against barbarians". The nomad faction leader sometimes used the Chinese military to aid in the defeat of his rivals and used favor with the Chinese to sever the flow of Chinese goods to his rivals. This allowed the nomad leader allied with the Chinese to increase his power and influence by using his near-monopoly of access to Chinese goods to gain supporters. This manipulation was especially effective in a segmemary lineage system in which exotic goods were used to enhance the status and reputation of leaders - that is, in a prestige-goods economy. Once the nomad leader became dominant he could either use his new power base to unify nomad groups and return to an outer-frontier strategy or leave them politically fragmented and consolidate domination in a limited region.

The oscillation between inner- and outer-frontier strategies was the mechanism that linked strong nomad polities with strong Chinese empires and fragmentation of nomad confederacies with fragmentation of the Chinese Empire. Only when the empire was strong could it be "milked" continuously via an outer-frontier strategy. When the empire was weak, nomad leaders tended to favor an inner-frontier strategy, making alliances with local "warlords."

This oscillation also explains the relative permanence of the "perilous frontier," as Barfield (1989) has dubbed it. Nomads could not rule a sedentary population without giving up their nomadism. Conversely, however, sedentary states could not conquer nomads - except by sedentarizing them. They could control them by a combination of constructing barriers and employing highly mobile troops, which could essentially beat the pastoralists at their own game - decisive hit-and-run victories (Lattimore 1962a, 485). Thus Central Asian pastoralists, especially the Mongols, could build huge empires, but could not maintain them. Conversely, the Chinese could manipulate, but never conquer, their nomadic adversaries. The sinicization of nomads has been noted often, but the "Mongolization" of frontier Chinese has been noted rarely (e.g., Lattimore 1940, 1962a).

The Afroeurasian-wide effects of the oscillation between inner- and outer-frontier strategies reverberated along the steppe gradient and were sometimes manifested by the movements of mounted pastoralists to the west. When the Chinese world-system became multicemric the associated steppe confederacy would also fragment. Among Central Asian pastoralists political conflict was often settled by migration of the weaker party into new territory. Since the confederacy that had formerly been allied with the Chinese Empire was often initially larger and stronger than its rivals located further from China, it could conquer or displace them. This often led to a net displacement westward of nomadic groups. In short, the core region in western Asia was subjected to repeated invasions by the losers in a long chain of displacements. In Chapter 10 we present comparative evidence that shows a synchronization of the rise and fall of empires and the growth and decline of cities in the Far Eastern and Central PMNs. It is our hypothesis that the main cause of this synchronization was the core/periphery process described earlier in which Central Asian steppe nomads interacted with agrarian empires on both ends of Eurasia.

We are not arguing that nomad raids were the main cause of collapses of Chinese and West Asian empires. Imperial collapses were to a large extent due to overexten-sion and diminishing returns (Tainter 1988; Hopkins 1978a). But these dynamics often initiated migrations, and intensified nomad raiding accelerated the processes of imperial demise.

The analysis of steppe empires has interesting implications for debates about the role of class relations in state formation. In traditional Marxist accounts, states only arise after classes are formed. Though there were differences in wealth among Central Asian nomads, to call these classes is an overstatement. Furthermore, there was the recurrent problem that when these "states" collapsed, the nomads reverted to "tribal" organization. The problem here is the assumption that state formation is entirely endogenous. Steppe empires were the only purely "tributary" states in the sense that the surplus that they extracted was from other states, not from their own peasants. The formation of steppe confederacies was a process that can only be explained by taking world-system relations into account. But this was an unusual case in which the less complex and hierarchical periphery (in terms of core/periphery differentiation) exploited the more complex core region. It is this case more than any other that justifies our insistence that the relationship between core/periphery differentiation and core/periphery hierarchy must be empirically studied in each case.

There is a sense in which the steppe confederacies may be understood as semiperipheral. If we consider the Chinese Empire to be the core, the remote nomads to be the periphery, and a steppe confederation to be the semiperiphery, we have an intriguing process for world-system theorizing. The semiperiphery grows because of unequal exchange in its favor with the core, and it uses its power to block the formation of rival semiperipheries. Yet it remains dependent on the core in the sense that this relationship is contingent on prosperity in the core region.

The contradiction of the semiperiphery s exploiting the core is resolved to some extent by the consideration of relative sizes. Chinese states typically were one hundred or more times more populous than steppe confederacies. Hence what they gave to steppe nomads was relatively minor in comparison with other exchanges but vital to the nomads. That is why the same exchange was seen by nomads as a matter of "tribute," whereas the Chinese always thought of it as "gifts" or "bribes" (Jagchid and Symons 1989, chaps. 2 and 4).

The nonstate peoples that Rome faced were more varied and presented a different set of problems (Dyson 1985). Along the eastern and southern (that is. North African) limits of the empire the nonstate peoples were broadly similar. On the European borders, peoples varied from shirting cultivators to complex chiefdoms. As is typical when states encounter nonstate societies, Rome exerted considerable, if uneven, pressure toward political centralization among its nonstate neighbors.

West Asian nomads differ considerably from Central Asian nomads. The kinship structures of West Asian and North African nomads were generally less amenable to expansion by "fictive" kin incorporation. This may have reflected important geographical differences (narrow valleys versus open plains) (see Barfield 1990). Most nomads on the eastern and southern limits of the Central PMN shifted more readily any more often between sedentary and nomadic lifestyles (Cribb 1991). This may have been because these nomads, especially in North Africa and in areas where they occupied highly varied terrain, were often transhumant. Because of this, they often had a much more symbiotic relationship with the sedentary agriculturalists within whose territory and economy they were tightly embedded (Barfield 1993, 94).

Finally, Roman strategy toward nonstate societies differed considerably from that of the Chinese and even that of the Parthians, Seleucids, Sassanians, and other West Asian states. Consistent with its early federation strategy, Rome often sought to enlist erstwhile nonstate foes as allies. Their strategy alternated between what Ross Hassig (1992) calls territorial (or direct) and hegemonic (or indirect) control.

D.J. Mattingly (1992) notes in his analysis of Roman conflicts with North African nomads that contrary to Edward Luttwak's (1976) famous analysis of Roman strategy, they did not always try to keep nomads out, even in the late empire. "Roman frontiers of whatever type (walls, earthworks, rivers, mountains, deserts, or road and fort networks) were not intended to be lines of blockade or first defenses against invading forces. Rather they were filters, designed to facilitate observation and supervision of movement between the territorial and hegemonic zones" (Mattingly 1992, 56). In other words, Rome lured nomads into an inner-frontier strategy and impeded a shift to an outer-frontier strategy by a judicious combination of tribute, alliances, and divide-and-conquer techniques (Mattingly 1992, 54). The geographic and kinship differences that we noted earlier reinforced these techniques.

Because of these differences, Rome seldom if ever faced concerted nomad confederations of the type that challenged China. This, however, did not eliminate nomad threats and impacts on Rome and the other large empires of the Central PMN. In Central Asia it was the cycle of nomad confederacies that caused the synchronicity of border warfare in China and Rome and drove the unification and dissolution of the Afroeurasian-wide prestige-goods and information nets. However, war and migration were only part of the nomad connection. The steppe peoples also were important links in trade.

Though steppe nomads played important roles in trade, they were not the fundamental cause of the strong flow of trade that developed along the Silk Roads. Significant differences in the internal dynamics of Rome and China fueled the demand for trade between them. Roman expansion was driven by the dynamics of elite competition, a need for slaves to work unoccupied land, and employment for Roman citizens (Hopkins 1978a). The legions attracted free peasant producers from the countryside, and large slave-worked plantations replaced the small farms. The demand for both urban and agricultural slave labor was great, which in turn provided an additional incentive for military expansion and the taking of war-captive slaves.

Elite competition was expressed in military adventures abroad and in conspicuous consumption at home (Hopkins 1978a). This led to a tremendous demand for luxuries through which elites could demonstrate and validate their status and wealth, which entailed a strong demand for "exotics" (see Helms 1988). Silk in particular was highly sought because of its luxurious and exotic qualities and because there was no local substitute or near-equivalent.

China, in contrast, expanded by incorporating new territory, transforming incorporated peoples into Chinese peasants, and thus expanding its tax base (Lattimore 1940). The demand for trade in China seemed to vacillate. Early Han efforts to set up trading bases in "Ferghana" (in what is now Afghanistan and was then part of the so-called "Western countries") indicate that the desire for trade was sometimes strong. While the Chinese exported silk and sometimes sought new markets for it, the west supplied little that the Chinese wanted besides gold. Thus, in general, the Roman demand for trade was greater than the Chinese demand.

Trade from Rome to China passed through many middlemen, and numerous subsidiary statelets sprang up along the Silk Roads to profit from this trade. Sometimes nomadic groups formed alliances with these new statelets and even occasionally took on the trading role themselves. Many groups sought to monopolize the trade, but the plethora of would-be carriers and the existence of alternative routes made this nearly impossible.

Silk did not travel directly from China to Rome. Rather, it passed through several stages. At the eastern end of the trade many local lords, either nomad leaders or rulers of the "Western countries," acquired more silk than they could consume, either themselves or as "gifts" to followers or payment for other goods or services. Hence many local states and nomad leaders acquired a great deal of surplus silk, and they actively sought new markets for it. Indeed, silk was so common, it was often used for money.

Silk left the "Western countries" by several routes (see Map 8.3). The trade passed through and sometimes around India, and then to Rome either along the coast - either overland or by short sea voyages - or, beginning sometime in the first century C.E., across the Arabian Sea. Alternate routes passed through Parrhia and other West Asian states. Silk was often processed, including unraveling and reweaving, in Syria on the borderlands between the Parthian Empire and the Roman Empire (Hudson 1931, 91-92; Yii 1967, 158; McNeill 1976, 99).

Nomads played other roles in the trade, notably that of protectors of trade. C.G.F. Simkin (1968, 45-48) shows that the major cost of ancient trade, in contrast with early nineteenth century trade, was not that of transportation (in terms of labor costs) but rather the high costs of frequent raids while moving goods over long distances. There was clearly a need to protect trade from nomad raiding.

Trade could be protected and nomads held at bay by various combinations of granting access to local trade, paying tribute (often called "gifts" or "bribes"), or hiring nomads as protectors. When these protectors were part of a strong confederacy, the protection was good. However, if the confederacy began to disintegrate, the /now-compering factions - along with former enemies - would increase their raiding in order to acquire either some of the goods being transported or their own rewards for protection. Thus anything that undermined a steppe confederacy would severely disrupt trade.

Once the trade began, it grew by expanding to other goods, and it led to general prosperity. This trade constituted an elaborate type of prestige-goods system. Bulk goods did not travel far, but their exchange increased in both volume and range, which furthered the use of silk as a medium of exchange in western China. It also led to some expansion of grain production and trade in order to feed the various officials and armies sent to the western borders by Chinese officials to promote and protect the trade (Yu 1967, 143-149).

What was the role and value of dlis trade to Rome and China? Given the lack of records this is extraordinarily difficult to determine. Beyond the paucity of data there are severe problems of comparisons of the value of trade in tributary systems. Tributary systems, despite the wealth they amass, remain largely subsistence economies. One can argue, as Simkin does (1968, 45ff.), that the appropriate comparison is not between value of trade and of all production but rather between value of trade and state expenses and revenues. The former comparison would render the trade almost insignificant; in the latter it would be substantial.

On the basis of estimates from Pliny (who wrote in the first century C.E.), Simkin (1968, 45) argues that the total value of eastern imports - most of which came through India - was about one-half of the total annual tribute collected in the first century B.C.E., or about two-thirds of Tiberius's treasury. The treasury ofWang Mang, emperor of China in 23 C.E., was twenty-two times larger than Rome's annual imports. While these comparisons must be taken with due caution, they reinforce the points that the trade was more important in Rome than in China and that it was substantial.

During the second century C.E. this trade began to decline. Again, records are sparse, so much of what happened must be pieced together from various types of evidence. In addition to silk and a few other exotics, technologies, ideas, ideologies, and pathogens also were exchanged. The latter produced devastating effects in both Rome and China (Bendey 1993; McNeill 1976, chap. 3). At the far ends of the trade circuits human populations were exposed to new and deadly diseases that rapidly became epidemic. These epidemics had both direct and indirect effects.

Directly, loss of population undercut the capacity to conduct trade. Producers and consumers of silk were lost; various secondary artisans who supported the trade were lost; the population of traders declined; and the food-producing population that sustained all of the others declined. Population decline and attendant loss of prosperity gave rise in turn to several indirect effects. McNeill (1976, chap. 3) argues that severe population losses, from one-quarter to one-third of the population, undercut the ability of the peasant population to support those dependent on it. This severely curtailed the power of central governments and contributed to and perhaps caused the collapse of those governments and gave rise to internal conflicts - which disrupted trade as well.

The disruption of trade curtailed the middleman and protector roles of nomads and oasis trading cities and hence their sources of revenue. Nomad rulers had used wealth siphoned from this trade to build confederacies and to expand their spheres of influence. Trade in grain and the establishment of military agricultural centers (Yii 1967, 43ff.) had allowed the population of some local oases and caravan-serving cities to exceed local ecological carrying capacity. For sedentary occupants this meant that they had to emigrate when trade declined. For some nomads the decline in trade undercut the alternative sources of wealth, undermining political confederations. This led in turn to the movement of nomadic groups, each displacing the next, and setting off migrations and raiding at both ends of Central Asia. Raiding, in turn, further disrupted relations and may have furthered the spread of disease. Given the number of parallel routes and the lucrative rewards of the trade, trade continued, but at an abated rate.

Continued trade actually intensified the effects of new diseases. To see how this is so, we point to research on the effects of disease on North American Indians. Russell Thornton and his students (Thornton, Miller, and Warren 1991) have modeled the effects of repeated exposure to new diseases on population recovery. They find that population decline may continue, and recovery may be extremely slow, depending on the timing of the repeated exposures, population growth rates, and especially age structure and age-specific mortality rates.

These same factors may shape the rate at which a population develops immunity to the new disease. The process involves an increase in antibodies in those exposed to the disease as well as changes in the microorganisms causing the disease that lessen their mortality effects. The timing of exposures also effects the development of immunities and the transformation of virulent diseases into "childhood" illnesses.

If more than a generation passes without exposure, the second exposure will approximate a "virgin soil" exposure. This will cause severe population losses. It is important to note that severe population losses are due not only to the disease itself but also to the severe disruption of the social fabric. Often this disruption means that simple health inputs such as supplies of food and water for the infirm are disrupted, which in turn may increase the mortality rate tremendously.

Some combinations of these factors may lead to very severe population losses - half or more - which persist for centuries. Indigenous populations in North America lost on the order of 90 percent of their population and only began recovery at the start of the twentieth century (Thornton 1987). The recovery of Native American populations was slowed by the effects of colonialism (Stiffarm and Lane 1992), including warfare. In small groups these effects could destroy all semblance of social structure and order. Those that do survive often flee the territory and are absorbed into other groups. When this does not spread the disease, it leads to significant reorganization of the social landscape. Small groups subject to these conditions are also readily susceptible to recruitment into new religions (Thornton 1986). Larger groups are somewhat better able to withstand the rapid population loss. Here again, there are parallels in the ancient world. Civil wars, rivalry among core states, and nomad invasions would have promoted similar effects.

Hence for regions at the ends of the Silk Roads, population declines were probably quite severe, which could have been a major cause of the relative decline in trade from 200 to 600 C.E. The effects on infrasocietal class and ethnic relations of these changes remain unclear. It is important to note that trade did not stop completely, but it declined sharply. The differences in the epidemics in Rome and in China were no doubt due to the differences in the various ancillary factors that amplified or attenuated the effects of exposure to new pathogens.

Similar processes may have affected South Asian states but probably much more weakly. To the extent that trade was seaborne, and if the sea journeys were longer than the incubation period of diseases, trade may have been far less severely disrupted. This may be why changes in South Asia were only loosely coupled, if at all, to changes in Rome and China, which as we have seen were more tightly coupled. McNeill (1976) suggests another reason. Due to a warm, humid climate, populations in India may have already developed immunity to some of these diseases. Hence trade would not have unleashed epidemics, or at least not of the same magnitude.

Thus military activity along the frontiers of Rome and China had major effects on surrounding peoples by increasing both intertribal and state-tribal warfare (see Chapter 4, and also Ferguson and Whkehead 1992a). Tribal peoples were often drawn more tightly into these world-systems through prestige-goods economies as states used their monopolies of access to luxury goods to influence and sometimes control local tribal leaders. The success of this strategy increased the demand for luxury goods, increased trade and traffic, and hence spread disease. Thus the Afrocurasian system became more integrated, but that integration led to subsequent, temporary disintegration of the system.

Sometime around 600 C.E. trade began to recover. According to Jerry Bentley this recovery "depended again on the foundation of large imperial states, such as the Tang, Abbasid, and Carolingian empires, which pacified vast stretches of Eurasia, and on the cooperation of nomadic peoples who provided transportation links between settled regions" (1993, 27). New trade routes across the Indian Ocean opened other avenues of trade not subject to nomad raiding, but subject to vagaries of wind-powered navigation and to disruption by a different kind of nomad - pirates. The significance of alternate routes offered by the sea lanes should not be minimized.

Sailing the sea lanes relied on the monsoons in the Arabian Sea, the Bay of Bengal, and the South China Sea, and these routes brought new peoples into the trade circuits of the Afroeurasian system (see Map 8.4). Indian and Chinese influence in Southeast Asia and Melanesia strengthened and expanded, incorporating formerly isolated local world-systems into the Afroeurasian PGN. The growth of trade on the sea routes meant increased competition with the Silk Roads.

Islam too spread along these routes, serving as an ideological integrator throughout much of the enlarged and more tightly integrated Afroeurasian PGN. Philip Curtin's (1984) study of trade diasporas and trade ecumenes is relevant to developing an understanding of the power of Islam as a cross-cultural integrating force. Curtin points out that specialized ethnic groups often play the merchant role in cross-cultural trade because distant kinsmen can trust one another. So cross-cultural trade is often in the hands of an ethnic "trade diaspora." As cross-cultural trade becomes more dense and regularized, the ultimate consumers become more familiar with one another, and cross-cultural understandings sufficient to underwrite longdistance trade emerge. The specialized trading ethnicities then lose their control as a trade ecumene emerges. Islam was a powerful combination of trade diaspora and trade ecumene: Because it is an evangelical "world religion", its traders not only trusted one another but also converted the peoples with whom they traded, thus creating a trade ecumene.

In this phase commerce along the Silk Roads and oceanic paths reached theretofore unprecedented levels in world history. In world-system terms, the incorporation was tighter but remained at the level of the prestige-goods net. But as we have noted, local bulk-goods production and regional political/military dynamics were also partly reorganized because of integration into the larger PGN.

Conventional accounts of Chinese history follow the succession of Chinese dynasties: Sui 581-618; T'ang 618-907, Sung 960-1279. As is often the case, such conventions obscure more than they reveal (McNeill 1987, 321). The key events and processes in this era are the reunification of China under the Sui and early T'ang rulers, the opening of the Grand Canal between the Yellow and Yangtze Rivers, the change in center of population density from the Yellow to the Yangtze River valley (which was tied to the shift from field grains to rice paddy agriculture), several military losses in the mid-eighth century, and the attempt to close the borders in the mid-ninth century.

These events and processes are all intertwined. Reunification under the Sui allowed new internal prosperity. It was tied with the gradual shifting of population centers to the south on the basis of an increasing reliance on rice cultivation and a gradually developing resistance to the more prevalent pathogens in the south. The increasing reliance on rice cultivation may have been the key change. Rice can produce more calories per unit of land than any other grain. However, this production requires huge amounts of human labor. The higher populations made more people available to impound water for more paddy and to build dams and dikes to control water. This in turn spread rice cultivation throughout the Yangtze River valley, further increasing population.

One of the water projects to emerge from these efforts was the Grand Canal, which opened in 605. The canal allowed a tremendous increase in commerce between the ecologically different Yellow and Yangtze River valleys, which now included bulk goods. This facilitated further development of and greatly increased the role of market exchange inside China (Chi 1963 [1935]). These changes also produced more wealth. Hence rulers could build larger treasuries without raising the tax rate.

The demand for labor undercut the ability of the state to maintain standing armies and thus made the use of "barbarians to fight barbarians" even more attractive. The increase in revenues made it relatively easy to continue the use of "bribes" and "gifts" to entice frontier nomads into alliances. However, when these armies met defeats at the hands of Koreans in 612-614 (McNeill 1963,463) and of Muslims in Central Asia in the eighth century, revolts erupted and China's overland trade with the outside began to decrease sharply. Complications arising from animosities over new religions led to proclamations closing the borders in 843-846, further curtailing overland foreign trade. The vast increase in internal trade rendered losses from the decline in external trade relatively inconsequential. Furthermore, the expansion of sea trade from southern China ports more than compensated for these losses.

The Muslim caliphates in the west (discussed later) blocked Indian trade connections with China via the Silk Road. Only the northeast, toward what is now Nepal and Tibet, was open to the spread of Indian influences. For the most pan this was an era of warring petty princes in India, with none achieving hegemony of any significant geographical or temporal extent. The seeds for animosity between Muslim and Hindu were sown, and Hinduism revived to become a dominant religion.

Much of the seaborne trade was taken over by Arab shippers. Most important here was increasing Muslim knowledge of the monsoon cycle in South Asia. This allowed the development of overlapping circuits of trade, most of which became dominated by Muslim merchants (Chaudhuri 1985). The first voyages all the way from China to Africa and West Asia were made in this era, although they remained quite hazardous. The Indie system was thus importantly affected by the Muslim expansion.

Two major developments occurred in the West Asian part of the Central PMN in this era, along with one seemingly minor change. First was the gradual development of the use of large horses and armored men to fight nomads. The roots of this development go back to at least the first century B.C.E. among the Parthians, but techniques expanded during the middle of the first millennium C.E. (McNeill 1982, 18-20; 1987, 28 Iff.). This allowed the West Asian stares some control of nomad assaults and played a significant role in shifting some of those assaults northward toward Europe.

The second major development was the appearance and spread of Islam. From the 630s on, Islamic religion erupted out of Arabia to conquer much of Western Asia by the mid-seventh century. By the mid-eighth century Islam had spread to the borders of China and India in the east and across North Africa to Spain in the west (see Map 8.5). The spread of Islam brought new knowledge, the revival of old knowledge, and the spread of new technologies to the west. It tightened the connections within the information net and created a very large trade ecumene. The role of Arabs in conveying the ancient classics of Greece to Europe is widely acknowledged. Charles Martel, building on knowledge gained in fights against Muslims, used mounted armed warriors in 732. This brought to Europe key technologies - large horses, alfalfa to feed them, armor for the men riding them, and stirrups both to make horses usable for shock combat and to allow the mounted use of crossbows. All these inventions played an important role in European knighthood and feudalism.

We must note that Islam was a singularly efficient "technique of power" (Mann 1986) for uniting faction-prone tribal peoples and small states. It also facilitated the expansion of trade in several ways. Besides the trade diaspora-ecumene aspect, the rise of Islam contributed to the emergence of the Abbasid Empire, which made trade safer. And within Islam, merchants were honored instead of disparaged (as they were in most tributary systems). Indeed, Muhammad had been a merchant. This made it harder for rulers to confiscate the wealth of merchants by casting it as "ill-gotten," which in turn reduced the pressure for successful merchants to use their wealth to buy titles.

A seemingly minor development in the sixth century changed the demand for trade with China. Traders succeeded in smuggling moth larvae of the silkworm into Byzantium, allowing the development of local production rather than merely reprocessing of silk. As this "import-substitution" industry developed, it lowered the demand for Chinese silk, facilitating other processes that were also undercutting trade with China.

During the early part of the era, when Muslim unity was strong, trade across the Sahara into West Africa began to develop. This eighth-century caravan trade brought gold and other sub-Saharan African goods to North Africa and thence to Europe and West Asia. It also brought Islam to West Africa. Trade and Islam combined with local development processes to cause the rise of states and empires in the region surrounding the bend of the Niger River near Timbuktu (Moseley 1992; Willard 1993). Thus did the Central PGN incorporate West Africa.

In the ninth century, under the Umayyad Caliphate, this new Muslim unity began to break down. Under the succeeding Abbasid Caliphate the unity collapsed into numerous warring states. Though this did not stop trade, it curtailed it because it became more difficult to move goods overland through warring states. This coincided with unrest in China, which also curtailed trade.

Several major changes took place in this region even as it became less tightly incorporated into the Afroeurasian world-system. The Byzantine (eastern Roman) Empire suffered setbacks on all sides and shrank somewhat before making minor expansions in the ninth century. The West became increasingly marginalized and isolated - to the south by Muslims, and to the north and west by hostile non-Christian societies and invading nomads. Long-distance trade declined and cities shrank. This isolation was a major factor in the development of European feudalism.

Still, major technological changes took place. Often overlooked but very important was the spread of the moldboard plow. This simple invention did two important things. First, rather than simply tearing a long hole in the soil as the scratch plow does, it turns the soil over. This exposes the roots of weeds to the sun and allows the tops to compost into fertilizer. Second, since the plow only turned soil to one side, when fields were plowed the same way year after year the net effect was to pile soil toward the center of the field, leaving trenches between fields, thereby building an effective drainage system. This was very important in the heavy, wet soils of northern Europe.

Though present in northern Europe very early in this era, the moldboard plow spread further after the Franks invaded. It opened new lands to cultivation as forests were cleared for farming. By about 1000 C.E. it was used widely in northwest Europe, with the overall effect of increasing the carrying capacity for human populations.

Alongside this change was the slow spread of the manorial economy and the use of mounted, armored men (knights) to defend territories. This, too, spread slowly but accelerated greatly under Magyar and Viking attacks in the late ninth century. Recently Klavs Randsborg (1991, 1992) has suggested that Viking raiding, which played an important role in the spread of knighthood, was due to decreasing trade with Muslim merchants via the Volga River route. The decline in trade lowered the supply of silver, prompting Vikings to seek it in raids on western European population centers. As with the changes in China, these changes were all complexly interlinked.

Europeans introduced one change in the mounted, armored warrior: the change from crossbow combat to shock combat used by knights. The diffusion of the stirrup was important because it enabled the warrior to stay on the horse (White 1962). The reasons for the shift to shock combat are unclear but are probably related to the limited utility of projectile weapons in heavily forested regions. In any case, these knights were singularly effective in combating invading, lightly armored nomads, whether they came by land or sea. However, they were not as effective along Europe's "steppe frontier" (McNeill 1964), where the absence of forests undermined their advantage and where their decreased mobility due to weight made them easy targets for highly mobile mounted nomads. Because of this, light cavalry was more prevalent in eastern Europe, and interestingly, also in Ireland (Bardett 1993, 70ff.).

Knights, however, were expensive to maintain. Prankish traditions of equality slowed the spread of the manorial system often used to support knights because of resistance to the enserfment of peasants. However, when nomad attacks increased, the resistance declined and the system spread, giving rise to what we know as the classical European feudal system.

The similarly gradual spread of Christianity and the attendant spread of Latin as the official Church language facilitated continued communication and cultural unity across many warring local kingdoms. Within this system towns held a somewhat anomalous place. They were not part of the growing feudal structure, but existed more or less outside of it. Townsmen were able to play one local lord against another to maintain independence; all lords had an interest in maintaining towns, whose merchants supplied them with luxury goods. Towns began to grow late in this era, but did not become large until sometime after 1000 C.E.

In the expansion phase of the period from 600 to 1000 C.E. incorporation was both wider and deeper than in the previous era. Parts of sub-Saharan Africa, Southeast Asia, and some of northern Europe were pulled into the Afroeurasian PGN. In the declining phase the system became more differentiated. Yet within each of these areas integration became somewhat more intense, albeit in different ways in the various regions. In China, due to the labor and water requirements of rice cultivation, the borders between the steppe and the sown became much sharper than on the western edge of the steppes. In western Asia and in Europe the climatic zones of arable land and pasture land overlapped extensively. Hence more land was subject to dispute for use in one or the other production technique.

The spread of Islam and trade contributed to sharper barriers between Islam and Christianity in the West and between Islam and Confucianism in the East. Thus, as Michael Mann has observed (1986), religions as "techniques of power" are singularly effective in uniting empires, but they also build barriers between empires by defining competing ideologies and identities.

In Central Asia, Tibetan Buddhism played an important role in producing some cultural unity. According to Christopher I. Beckwith (1987a, 7), "Of all the effects of the Tibetan expansion, the most long-lasting was not primarily political, but rather cultural in nature." In some cases Buddhism was sufficiently strongly adopted to enable the Tangut Empire to resist the onslaught of Islam (see also Beckwith 1987b, 1987c). While we suspect that there was more to it than this, the important role of religions cannot be denied.

The ways in which northern Europe became more, then less, incorporated shaped the course of social change there. The rise and subsequent transformations of northern European social organization were intimately bound up with the changing interconnections to the Afroeurasian PGN and IN. The failure to attend fully to those connections is the fundamental source of the inadequacies of so many explanations of the rise and demise of European feudalism.

In the fifty years before and after 1000 C.E. massive changes in Eurasia were under way. Populations in both the eastern and western ends of the Eurasian land-mass had achieved an equilibrium with pathogenic microorganisms, and so population, economic production, and productivity increased. Northern European towns began to be founded - or refounded - and to grow dramatically. Trade within northern Europe and between northern Europe and the outside world increased. For the first time in history some areas in northern Europe began to surpass Mediterranean Europe in wealth and productivity. These changes gave rise to the Eurasian world-system of the thirteenth century so wonderfully described by Janet Abu-Lughod (1987, 1989).

The most dramatic events of the entire era, however, were not trade and prosperity. Rather, they were the merging of most of the Afroeurasian PGN into a single political/military net via the Mongol conquests, and the subsequent systemwide depopulations due to incursions of the bubonic plague. These epidemics contributed to the disarticulation of this new, if ephemeral, Eurasian-wide PMN.

The Sung dynasty came to power in 970. As we have already seen, it furthered the development begun by its Sui predecessors. In this era prosperity revived. Much of this growth was fueled by the introduction of a new strain of rice that matured quickly enough to allow two crops a year (McNeill 1987, 327). This allowed further population growth, increased tax revenues, and increased surplus that could be traded.

Though this "green revolution" based on the new rice was the most spectacular in terms of effects on population, it was not the only new technology. Gunpowder was discovered and put to use in siege warfare, though it was used more often in fireworks. Since the major enemies of the Chinese were nomads, there was little use for heavy artillery, and warfare was not an art esteemed for its own sake (McNeill 1982, 330). The compass was in use by 1100, allowing Chinese ships to navigate more reliably on the open seas. The general productivity of the economy is reflected in iron production, which reached levels not attained in England until 700 years later (McNeill 1982, 26-27). The Sung economy also evinced a high degree of commercialization. Paper money was used, and George Modelski and William R. Thompson (1995) claim that Kondratieff waves (forty- to sixty-year business cycles) can be inferred from the sequences of economic growth and stagnation that occurred during the Sung dynasty.

There was, however, a key gap in Chinese prosperity. Following now-ancient techniques for dealing with nomads, the Sung never controlled the north. Indeed, the Khitan state (known as the Liao dynasty, 907-1125) ruled the north from Beijing until supplanted by the Manchuria-based Jurchens, who conquered it in 1123 and ruled until 1234. The Jurchens expanded their territory southward almost to the Yangtze River. They also unleashed more movement of nomads along the steppe gradient and indirectly contributed to the rise of the Mongol confederacy led byTimujin, known as Chinggis Khan.

Khubilai, a descendant of Chinggis, conquered and became ruler of China in 1259 and founded the Yuan dynasty (1260-1368). Typical of Mongols, he favored trade, took knowledge where he could get it, and treated knowledgeable foreigners with respect. Marco Polo, the famed Venetian merchant, served in his court as an adviser from 1275 to 1292. Under Mongol rule trade across the Silk Road increased considerably.

When the Mongols were overthrown and replaced by the Mings in 1368, the capital was moved to Beijing because of fears of further Mongol attacks. The need for soldiers in the north, the fear of rival centers of power, a need to assert central imperial control, and a general disgust with foreigners and traders led the Mings to forbid overseas expeditions in 1424. They delayed enforcement of the ruling so that Admiral Zheng He (Cheng Ho) could make one last voyage (1431-1433) to India and Africa (Bentley 1993, 168-170; Levathes 1994).

The withdrawal of the Chinese left the Indian Ocean open to European penetration with minimal opposition a few decades later. Had the Chinese remained a more active maritime power and continued their expansion into the Indian Ocean, their clear naval superiority would doubtless have made it much harder for Europeans to gain a foothold in the Indian Ocean trade. This was even more the case in the South China Sea.

During this era Japan's feudalism expanded. Like England in the West, Japan was somewhat protected by virtue of being surrounded by the sea. A timely storm and organized resistance allowed Japan to repulse an attempted Mongol sea invasion in 1281. This bolstered Japan's sense of power and dampened Mongol enthusiasm for mixed sea-land ventures. Superfluous Japanese samurai, that is to say, sons of nobility without land, were further inspired to take their military prowess to the sea. Many of them became pirates preying on coastal trade as far south as Southeast Asia. This contributed to the growth and independence of coastal Japanese towns. Still, for all these changes, the major story of this era is that of the Mongols.

The Mongol conquest was probably the most world-changing event of this era. We follow Barfield's account and interpretation of it: "The exceptional nature of the Mongol Empire has been largely misunderstood because, as the most powerful nomadic state that ever existed, it was presumed to be the culmination of political evolution on the steppe rather than the exception that it was" (Barfield 1991, 48). The entire sequence was exceptional in several ways; in Chinggis's rise to power, in the Jurchen reaction to it, in the extent of the conquest, and in the establishment of several different city-based states, including the Yuan dynasty.

Chinggis rose to leadership from a very marginal position. Often even his own relatives opposed him. Consequendy he did not rely on kinship to organize his supporters but rather on loyalty and autocratic control. His multitribal elite was drawn from friends and retainers:

Chinggis's political organization was not, therefore, the culmination of a long evolving steppe tradition because it rejected the imperial confederacy model. Instead, the Mongol state was based on the principles of centralized administration, the destruction of tribal patterns of leadership, and a rigid discipline to a degree previously unknown among nomads. It was a unique creation. After the fall of the Mongol Empire the nomads reverted to the older and more traditional imperial confederacy model of organization (Barfield 1991,49).

This new-style state then confronted a Jurchen state in northern China, itself a semiperipheral marcher state out of Manchuria, that refused to follow the time-honored Chinese path of appeasement. In pursuing the familiar outer frontier strategy of destructive raids to inspire appeasement, Chinggis overplayed his hand and somewhat reluctantly conquered northern China. This, along with Chinggis's low tolerance for resistance, led to widespread destruction of cities and agricultural infrastructure. It was only with Khubilai that the Mongols took up the responsibility of ruling northern China rather than despoiling it.

The Mongol Empire for the first time united most of Eurasia into a single empire - although, to be sure, the merger was far from complete (see Map 8.6). Egypt and North Africa were not militarily incorporated because of the strong resistance of the Mamlukes. Western Europe remained outside the Mongol Empire, in part because of the inhospitably of forest zones to mounted archers (Lindner 1981, 1983) as well as the success of knights in the forest zone (McNeill 1963, 1964, 1982) As noted, Japan repelled Khubilai's seaborne invasion in 1281 (McNeill 1982, 43).

Mongol success can be attributed to factors and processes occurring at different levels simultaneously (Saunders 1971; Morgan 1986; Lindner 1981, 1983; Barfield 1989). First, the states they attacked in western Asia were weak and vulnerable to conquest. Their ecological adaptations were much more fragile than was the case in China. The Mongols, unaware of this, attacked with vigor. Whereas in China destroyed towns were eventually rebuilt and repopulaied, in southwest Asia such destruction often became permanent, especially when irrigation systems were ruined. Mongol aversion to local administration frequently left no one capable of rebuilding destroyed systems (Barfield 1989, 201-202).

Second, continual warfare made a client relationship with the Mongols an attractive "bargain." Polities that accepted Mongol terms (in Manchuria, Korea, Uighar oases) were not destroyed and often kept their own leaders. Polities that continued to resist the Mongols or repudiated treaties (Chin China, western Turkestan, and the Tangut kingdom) were punished and often destroyed.

Chinggis was particularly intolerant of disloyalty. Punitive wars "were so devastating that they led to the overthrow of the ruling dynasties and, by default, their direct incorporation into the Mongol Empire" (Barfield 1989, 200). This was different from all previous Central Asian nomad conquests. In the west they destroyed some states and were forced to incorporate and administer others. In the east they were ultimately trapped by their own vigor into founding a new dynasty in China.

A third factor in Mongol success was the continued presence of pastoral nomads who maintained a flexible kin-ordered social structure that allowed them to recruit other nomads and even sedentary groups into a larger and larger machine for conquest. By choosing leaders for loyalty and performance, Chinggis built a command structure that would not easily segment along tribal lines.

Fourth was the presence of several leaders who astutely balanced the drive for conquest and plunder with the needs of administration. According to Thomas T. Allsen (1987), Mongke (Khubilai's brother) was able to implement administrative innovations by keeping conservatives occupied in (successful) battles, giving him a free hand in the center.

As Rudi Lindner (1981, 1983) notes with regard to the Ottomans, analysis based on powerful leaders is not a reversion to a "great man theory" of history. Rather, it is a recognition that Mongol leadership was a form of big-man leadership (Sahlins 1961, 1963, 1968; see also Chapter 3) that was strongly shaped by an especially competent leader. Specifically, Mongol leaders were able for some time to maintain a sufficient volume of plunder and tribute to ensure the loyalty of tribes that might otherwise have been inclined to leave the confederation. In short, internally they perfected the outer-frontier strategy of "milking" sedentary states, even as externally they overplayed it.

A fifth factor in Mongol success was superior logistic ability in military communication, transportation, and movement. This superiority was rooted in the pastoral way of life: ready availability of horses, intimate knowledge of geography, and ability to move their entire means of production (families and herds) with them. Utilizing these advantages, all the great khans - if only temporarily - were able to capitalize on their inclusive kinship structure and permeable group boundaries. Conquered groups could switch allegiance rather than die fighting a losing battle. This worked well with other pastoralists and less well with sedentary peoples. Continued expansion alleviated the problem of revenue by a constant inflow of booty. It also minimized factional rivalry and quieted objections to the changes that came with empire. Superior communications and mobility facilitated the formation of large armies. However, these advantages were inherently unstable, and hence temporary.

This instability was rooted in political and technological problems. The political problem lay in the succession of rulers. A big man comes to power on the basis of his personal skills, not the least of which are alliance building and warfare. Hence succession to rulership required demonstrated success in fighting. For the Mongols these problems were exacerbated by the competing, and at times conflicting, principles of lateral and lineal succession. The lack of clear priorities inevitably led to succession by arms. Institutionalization of succession would have undermined the very basis of leadership. Hence it is not simply that the Mongol Empire failed to institutionalize political succession (as Eisenstadt [1963] argues), but that Mongols could not institutionalize political succession and remain Mongols. The same problems were inherent in political control and revenue garnering.

Mongol superiority in communication and mobility of warriors and resources also contributed to instability. These capabilities were crucial parts of pastoral life and were available to all pastoral groups and leaders. This made it impossible for any one leader to monopolize control of strategic resources as a means of coercing compliance. Dissenters could simply fold their tents and leave with their herds.

The material basis of this situation was the adaptation to the volatile and uncertain steppe environment. A flexible kinship system, a fluid form of leadership that can respond quickly to changing circumstances, and a pastoral economy together form a highly adaptive culture for living in a volatile steppe environment. Though this culture was very effective for organizing mobile armies of conquest, it also created inherent limits to expansion. It was not well adapted to the administration of sedentary agricultural production. Thus the edge of the steppe remained a permanent frontier (Lattimore 1940; Lindner 1983; McNeill 1964; Whittaker 1994).

Mongol unity, which lasted little more than a century, brought major changes. It opened a third, northern, connection between China and Europe, directly over the steppes, bypassing connections through what is now southern Iran and Iraq or through the Indian Ocean. The steady traffic across the steppes opened other circuits of trade: "Gradually a north-south exchange of slaves and furs for the goods of civilization supplemented the east-west flow of goods that initially sustained the caravans" (Bentley 1993, 56).

One of the most important consequences of Mongol unification was the transmission of a hitherto isolated rat-and-flea-borne disease - the Black Death, or bubonic plague - to Europe and China (McNeill 1976). The Black Death first swept through China in 1331, causing immense population losses, and through Europe in 1348, ultimately killing one-third to one-half of the population and thus fundamentally altering relations between lords and peasants. It took Europe over a century to recover.

According to McNeill (1976, 132-175), the Mongol role in the spread of the plague may have also been an important cause of their own undoing. Briefly, the bacillus Yersinia pestis (also known as Pasteurella pestis) may have been moved by Mongols from Manchuria to the Central Asian steppes, where it became endemic among native rodents. From there it was spread to both China and Europe and may well have infected many Central Asian nomads. If so, this would be another factor in slowing Mongol expansion. The spread to China in 1331 would have contributed to undermining the strength of the Yuan dynasty, which fell in 1368. Finally, this would explain why, after the fall of the Mongol Empire, net migration was onto the steppe by sedentary peoples, rather than movement from the steppe by nomads. The pathological consequences of the Mongol conquest were clearly as dramatic as the political-economic consequences.

Sometime around 1000 C.E. Turkish tribes began moving from the steppe into various western Asian regions. In many ways this was more important than the initial spread of Islam because the tributary empire they helped to build was so powerful (Barfield 1990). The movement seems to have been motivated by the usual steppe gradient factors: fierce competitors to the east, more attractive lands to the west. Most of the Turks accepted Islam, albeit lightly. Many Turks became effective, if troublesome, troops for the Abbasid rulers in Baghdad. Their acceptance into the Muslim world generated a great deal of political unrest and disorganization. Still, they were a major factor behind much of Muslim expansion in this era.

"Seljuk Turks filtered into Asia Minor," writes McNeill, "and after the Batde of Manzikert (1071) pushed the Byzantine frontier back nearly to Constantinople" (McNeill 1987, 375). This provided one justification for the first Crusade in 1096. By 1099 the crusaders captured Jerusalem and left behind a series of small states along die eastern shore of die Mediterranean. Their success was as much due to Muslim political disarray as to their own efforts. This was the only Crusade to reach Jerusalem. Saladin recaptured Jerusalem in 1187 and destroyed nearly all of the Prankish states.

Muslim traders spread down the coast of East Africa and destroyed the West African kingdom of Ghana in 1096. Many Central Asian groups were converted to Islam, and a few Muslim communities developed in western China. Between 1000 and 1200 Muslims nearly doubled the territory they held.

In the thirteenth century much of Muslim territory was overrun by the Mongols. Baghdad was sacked in 1258. The Ottoman Empire was built by Turkish warriors. In the fourteenth century the Turks crossed into Europe and defeated the Serbs at Kosovo in 1389. Though the territory influenced by Islamic religion was not reduced, the Mongol conquests shattered Muslim unity, and the old West Asian core region never regained its prominence.

Shortly after 1000 C.E. some Turks left western Asia and invaded northern India. By 1200 Muslims ruled northern India, consolidating their conquests in the Sultanate of Delhi (1206-1526). This brought the Indian subcontinent permanently into the Central PMN. Because these Turks wore their Islam lightly, they were able to make compromises with their Hindu subjects. This accommodation, along with the absence of any Mongol invasions, contributed to the stability of this state.

Why the Mongols never invaded India is not adequately explained. It would seem that the mountains and jungles were not a sufficient barrier, as indicated by Khubi-lai's incursion into what is now Myanmar (Burma) in the period 1283-1285. Because the Mongols used rapid postal systems built on horse relays to administer their empire, they may have realized that these administrative techniques would not work in tropical areas. This, along with higher mountain barriers, would have made the conquest of India less attractive. As noted, the trade across Central Asia offered an alternative to expensive routes through the mountains to India on the way west.

In the late tenth and early eleventh centuries Scandinavia, Poland, and Hungary became Christianized, spreading northern European influence and facilitating trade. As trade increased, towns began to grow and expand. By playing one lord against another and by using wealth to purchase independence, a relatively rare form of municipal polity began to spread throughout northwest Europe - towns that were more or less independent of any noble ruler and accustomed to self-governance.

Towns became attractive to peasants who wanted to escape harsh conditions of serfdom on manors. Though towns offered opportunities that did not exist on the manor, they also were frequently lethal to newcomers not adjusted to diseases borne of close living. Stadtluft machtfrei (city air makes you free) but also sometimes dead. To some extent, the availability of towns as an alternative to the manor gave peasants a somewhat improved bargaining position vis-a-vis nobles (Bartlett 1993).

In 1204 Venetians participating in the fourth Crusade attacked and conquered Byzantium, further consolidating their control of trade in the Mediterranean. Despite the ascendancy of the Venetians, the new prosperity in northern Europe brought population growth and moved the population "center of gravity" of Europe north of the Alps for the first time.

The Mongol conquests did not have direct effects in western Europe. The after math of the conquests, however, was devastating in Europe. As noted earlier, the bubonic plague, spread by traders traveling across the steppe, swept into Europe it 1348, killing between one-third and one-half of the population. As with earlier epidemics, this one returned periodically for several decades, and European populatiot did not fully recover until sometime in the sixteenth century. European prosperiti was undermined and economic and political conditions remained uncertain. The new shortage of labor led to labor scarcity and an improvement of the terms undei which peasants worked, both on the manor and in the towns.

Though the Mongol conquest was an exception to the steppe empire/agrarian empire pattern, it was not an anomaly in world-systems terms: Once again a semiperipheral marcher state conquered an old core by building on its middleman trading) role and military advantages. The Mongols broke from the steppe/agrarian pattern by overplaying the outer-frontier strategy. Instead of using violence to extort re sources from agrarian states, they attacked too vigorously and actually conquere some surrounding states, including China.

The Mongol conquest created a single Eurasian state that encompassed all but India and a few peripheral and semiperipheral regions. It temporarily linked the Central and the Far Eastern PMNs in to a single Afroeurasian interstate system (re call that the Indie PMN had already been incorporated into the Central PMN) However, this new multicored world-system was especially unstable, despite it being the most systemic of all Afroeurasian world-systems to date. The empire was simply too large to be maintained logistically. Following Randall Collins's "no inter vening heartland rule" (see Chapter 1), none of the potential corewide empires - the Mings, the Ottomans, or any of the local states in India - could mount an expedition to conquer any of the others. Even Timur the Lame's (Tamerlane, rule 1360-1405) rebuilt empire disintegrated upon his death, although in this case the lack of a rule of succession may have been a more important factor. Furthermore, the Mongols did not produce anything that was needed or wanted by the world market Even more than most tributary ruling classes, they were "macroparaskes" (McNeil 1992) whose wealth came from siphoning off some of the trade that traversed they territory or from extracting tribute from agrarian empires.

The Mongol conquest did, however, bring massive changes in the economic an political balances among the constituent world-systems. China's growing lead ii technology and productivity was set back as the Mings concentrated on protectin; their northern border from further nomad incursions. India was ignored and did no share in the new overland trade across the steppes. Western Asia was shattered by series of nomad incursions that reshaped the states there and undermined any semblance of Muslim interstate unity.

Meanwhile, in Europe, growing trade began the long process of increasing the strength of merchants and financiers relative to that of the kings, the nobility, am the Church. The opening of new pathways and increased favor toward merchants had whetted European appetites for further trade, and ultimately for more direct routes to the East. This was a major spur to European exploration of the globe in the following centuries. Janet Abu-Lughod (1987, 1989, 1993) suggests that it is not so much that the West rose as that the East fell. As far as the Chinese are concerned, though, the East did not fall; they simply took their ships and went home - leaving the field open to European upstarts. Abu-Lughod (1993) notes also that the Indian Ocean trade had not been dominated by any one trading group. Consequently the various competing traders were not accustomed to defending against rivals bent on hegemonic control of trade.

What do we learn about world-systems from this quick tour of two millennia of history? With respect to issues of continuity and transformation, we note similar patterns of change at the western and eastern ends of Afroeurasia - evidence that they were connected in a single system much earlier than many historians have thought. It appears that Indian and Central Asian states did not follow the same patterns, or at least not as closely. Both often played a middleman or broker role in exchange between the two core regions at the extreme ends of Eurasia.

Because both China and Rome were termini of trade circuits, they were tightly tied to shifts in volume and velocity of trade. India, however, participated in multiple circuits of trade - two for the China-Rome trade, and several others into East Africa and Southeast Asia. South Asian trade centers could shift either outlets or sources of goods, or both, to compensate for changes in other circuits and thus insulate themselves from the consequences of sharp decreases in trade along the various Silk Roads - including disruptions from epidemics. Interestingly, the two middleman areas, Central Asia and South Asia, experienced very different types of state formation. The steppe confederations were large and short-lived. The states of India were relatively small, and the few large empires that did emerge were usually not concurrent with large empires in western Asia or the Far East.

It is interesting to speculate about the extreme ends of this system: England and Japan. Both are islands, insulated from land invasions. Both developed feudal systems with towns that were more autonomous from the tributary social structure than was typical throughout the rest of Afroeurasia. Moreover, the timing of these developments in the two geographic extremes is close. If Japan had equally navigable rivers and accessible coal and iron deposits, as England had, would it have emerged even sooner as a contender for the core hegemon position in the modern world-system?

With respect to the issue of incorporation, the history of the Afroeurasian world-system makes it clear that incorporation need not necessarily entail peripheralization. Incorporation was involved in the transformation of three formerly autonomous world-systems into one larger, multicentric world-system. Furthermore, components of the formerly independent systems were significantly transformed by the merger. Contact with peripheral zones sometimes transformed those peripheral zones into semiperipheral or even core zones. In the most dramatic such merger in world history, the Mongol Central Asian periphery became for nearly a century the corewide empire of the entire Afroeurasian world-system.

Also, we must recognize that this merging of world-systems proceeded along at least two somewhat autonomous dimensions corresponding to the two networks that merged. The first was the trade dimension, which ranges, as noted, from longdistance trade in goods with a very high ratio of value to weight, to goods with a low ratio of value to weight. The second was the political/military dimension of regularized political relations, which may range from constant warfare to generalized peace. These two dimensions are not quite independent because intensive warfare all but obviates trade, whereas intense trade produces a major incentive for peace. Steppe nomad raiding was an unusual combination of the two dimensions that facilitated extraction of surplus from agrarian states.

If the four nets change and merge in somewhat different patterns, might it not also be the case that each net has its own key inventions (whether originating by independent invention or diffusion from another source) that are either causes of or responses to major changes? Religions, such as Buddhism, Christianity, or Islam, were important innovations in the information net and represented new techniques of ideological power. Stirrups, gunpowder, and shock combat were important innovations in the political/military net. The compass was important in both the prestige-goods and bulk-goods net. The list could be extended. Following the reverberations of any one of these inventions would be one way of tracing the impact of each of the networks on the others and on the world-system as a whole.

Incorporation of states or of non-state societies into the system is clearly a complex process as well as a matter of degree - not simply a binary "in" or "out of" the system. Cursory comparisons in the relations between Rome and its peripheral "barbarians" and China and its peripheral "barbarians" demonstrates that incorporation - even for non-state societies - is not a passive process. Rather, it is one that the incorporated peoples strive to control and manipulate. The Mongol experience, exceptional as it was, demonstrates that incorporated peoples, on occasion, may gain the upper hand.

The Afroeurasian system set the stage for the emergence of global hegemony by further developing the institutions of large-scale political control and the institutions of long-range trade. The development of large states and empires occurred in the context of a trade network that was larger than any state. Thus the political structure was most often multicentric even within PMNs, and this encouraged rulers to allow more autonomy to merchants. The growing commercialization of the tributary empires also was reflected in the commodificarion of land, labor, and wealth within empires. As we have seen, the cyclical gain in scope and strength of the large-scale prestige-goods networks created local demand for food and basic goods and stimulated the bulk-goods networks. Though bulk-goods production remained largely for the use of direct producers, the growth of cities created a demand for production of food for exchange. In the tributary empires the main mechanisms for ensuring the availability of supplies for the cities were the coercive institutions of the state. But markets played a larger and larger role in the later commercialized empires. As a result, the institutions that eventually allowed capitalism to become the predominant form of accumulation in Europe were developed in the commercialized agrarian empires, and especially by the semiperipheral capitalist city-states.

Besides the matter of the predominant mode of accumulation, there was another major difference between the Afroeurasian system and the Europe-centered global system that eventually emerged. Both systems were politically multicemric in the sense that no single state controlled the whole system. But the Afroeurasian system was multicentric in a much more fundamental sense. The three core regions were noncontiguous and were never part of a single PMN before the rise of European hegemony. They were integrated by prestige-goods exchange, and this had important systemic effects on all three core regions. But the system was not as systemic then as it was to become later, when all the core regions became part of a single interacting PMN. Thus, because the networks have all become global in the modern world-system, it'is much more a single system than the Afroeurasian system ever was.

Now we shall consider the similarities and differences among our whole panoply of world-systems large and small.

How does the comparative world-systems perspective modify our view of the modern world-system? This is our third "case study." Immanuel Wallerstein's interpretive; history of the modern world-system analyzes the emergence of agrarian capitalism out of the crisis of European feudalism in the sixteenth century and then tells the story of the system's cycles, trends, hegemonic shifts, and expansion to a global scale. Though we agree with the overall thrust of Wallerstein's analysis, our comparative perspective suggests a few changes.

Andre Gunder Frank and Barry K. Gills (1993a) argue for 5,000 years of continuity in the processes of hegemonic rise and fall, cycles of growth and stagnation, and exploitation of peripheral hinterlands. We agree with some of these continuities, but our spatial and temporal bounding is more nuanced, and we strongly disagree with the assertion chat no qualitative transformation of the mode of accumulation accompanied the rise of European hegemony.

Europe was composed of autonomous small-scale world-systems until the Bronze Age. The slow spread of horticulture and the Indo-European linguistic stock from West Asia resulted in a symbiosis between farmers and foragers in many of the Neolithic egalitarian systems of Europe (Renfrew 1987; Gregg 1988). Bulk-goods and political/military networks were quite localized, because their effects declined rapidly because of extremely difficult communications and transportation conditions. Local core/periphery differentiation existed between farming and foraging societies, but there was little in the way of core/periphery hierarchy. Europe became linked into a weakly connected long-distance information network through down-the-line diffusion of certain stylistic and technological ideas from the West Asian homeland of Neolithic farming societies and, later, early states (Sherratt 1993a).

The battles between diffusionists (lumpers) and local autonomous development theorists (splitters) have raged mightily among diose scholars who study the emergence of complexity in Europe. V. Gordon Childes (1936) difiusionism may have been somewhat overstated, though many of his claims have been substantiated by recent archaeological evidence. Though the kin-based egalitarian societies of Mesolithic and Neolithic Europe did not slavishly copy influences from the West Asian system, they adopted many types of pottery and tools that were then produced in local and regional styles. The exposure to influences emanating from the West Asian core also precipitated the building of megaliths in Europe.

Andrew Sherratt (1993a) summarizes the archaeological evidence for his explanation of the long-term incorporation of Europe into the West Asian Central System. Sherratt (1993a, figure 4) depicts the spread of farming, flat-based pottery, copper making, and the plow from southeastern to northwestern Europe. Some of these changes were introduced by migrations, whereas others were caused by the adoption of new practices by extant peoples. These linkages were not yet strong enough to constitute systemic interaction, and thus Europe was not truly integrated into the PGN of the Central System until the rise of Bronze-Age long-distance trade in prestige goods.

During the Bronze Age regularized down-the-line trade in prestige goods (bronze, amber, etc.) linked the Mediterranean, temperate Europe, and Scandinavia into the PGN of the West Asian system (Sherratt 1993a). The linkages tightened and relaxed and then tightened more tightly during the Bronze and early Iron Ages. European chiefdoms arose on the basis of new religious hierarchies and military organizations that used imported prestige goods as sacred symbols (Kristiansen 1987, 1991). The Iron Age brought new agricultural technologies that further increased the productivity of the land. Population densities increased and trade links again strengthened (Wells 1980, 1984; Sherratt and Sherratt 1991). Sherratt (1993a) contends that it was during the Iron Age that Europe first became integrated into the West Asian BGN as a producer of raw materials in exchange for the manufactured goods of the eastern Mediterranean core. The Phoenician capitalist city-states linked the whole Mediterranean littoral by direct trade with the West Asian and Egyptian empires. The rise of states in what is now Italy - the Etruscans and the Romans - brought most of the rest of Europe into the Central PMN and eventually into the Central BGN.

Rome integrated the villas of its provinces in Europe into the Mediterranean system of food production. From this time on, Europe was firmly part of the Central System. It was never again a separate world-system, despite the fact that it was temporarily cut off from the long-distance trade by the rise of the Islamic empires. Indeed, feudal involution was mainly a result of Muslim refusal to trade with infidels. Arguing that Europe was a separate system during this period is a mistake that is similar to that of arguing that the Soviet bloc was a separate system in the twentieth century because there was little trade with the West. In both cases enmity and competition had enormous systemic consequences.

This is one difference that we have with Wallerstein's interpretation. He argues that the modern world-system was a separate system from the tributary empires of West Asia. His argument does not hinge on separate economic divisions of labor haicd on the production and exchange of necessary (roods. Rarhcr. Wallcrwin invokes a different criterion - mode of production - for his contention that Europe was a separate system. Though we agree that Europe developed an especially concentrated and powerful form of capitalism, we do not agree that this means that it was a separate system. Rather, it was a subregion of a larger system throughout the period during which capitalism developed. Indeed, we cannot explain the emerging predominance of capitalism in Europe without understanding the earlier history of this larger context and the particular connections that Europe had with the larger system.

What occurred in Europe after the extremely decentralized feudalism of the later centuries of the first millennium C.E. was the formation of a regional core within which capitalism eventually became the predominant mode of accumulation. This was made possible by both the long development of capitalist institutions in the commercializing Afroeurasian PGN and the particular position that Europe occupied in that larger system during the period of regional core formation and capitalist transformation. Capitalist institutions were highly developed in the Hellenistic Mediterranean and in the Roman Empire. Capitalist markets, money, contract law, and the law of private property were all institutional developments that were well elaborated in Rome. The reemergence of capitalist commodity production during the European renaissance rediscovered these institutions and made effective use of them in the construction of a strongly capitalist system.

The weakness of territorial states in Europe was a function both of the demise of the (western) Roman Empire and the Muslim blockade. This weakness of centralized states made it possible for capitalist city-states to bunch closely to one another and to develop a strong regional system of commodity production and commercial finance. Though the existence of capitalist city-states was not new, their density in a small region in which there were no large tributary states was unusual. When larger states did emerge in Europe they combined tributary logic with a dependence on capitalism. Perry Anderson (1974a) has characterized the "absolutist" European states as "feudalism writ large." Although these states used feudal forms of legitimation and organizational ideology (the benefice and fief), the monarchs were often in debt to relatively autonomous merchants and financiers. Their abilities to make war on one another were constrained or facilitated by their access to resources controlled by these financiers.

The key to the emerging of the predominance of capitalism was not the unique cultural and organizational characteristics of European feudalism - either its parcellization of sovereignty" (Anderson 1974a) or the "normative pacification" of Christendom (Mann 1986). Rather, it was the context of European feudalism - a very decentralized, weak tributary mode of accumulation - embedded in the market forces of the Afroeurasian PGN that allowed capitalism to displace the tributary mode of accumulation. It was not the fall of the East but rather the continued strength of tributary states in West and East Asia that prevented capitalism from becoming predominant there. Europe was in the right place at the right time to host the rise of capitalist predominance.

The emerging European interstate system of small and medium-sized states was stabilized by strong capitalism. Capitalist accumulation provided an important alternative source of surplus product for states, to some extent reducing the pressure for tributary expansion. When empire builders did emerge, the coalitions formed against them were strong, though these still involved large tributary states. The rise of a capitalist nation-state in a core region in the seventeenth century - the Dutch Republic - was made possible by the already-strong world market and was itself the cause of the future strengthening of international markets. Though there had been many earlier capitalist states, these had been city-states occupying semiperipheral positions. The Dutch Republic was the first national state with core status to he controlled by capitalists. By combining the economic policies of city-states with the protective capacity of territorial states, the Dutch invented a new version of state power that led the developing capitalist regional system in Europe in the seventeenth century (Taylor 1994).

Once the pattern of hegemonic rise and fall had brought capitalist states to the leadership role, the chances of there being a restoration of the tributary mode were greatly reduced. It was at this point - the seventeenth-century Dutch hegemony - that capitalism became the predominant mode of accumulation in the European subsystem.

How was this transformation facilitated by Europe's insertion into the larger Central System? We have already mentioned that the prior development of capitalist institutions in Rome and China created a cultural, legal, and economic heritage that was conducive to capitalist.development. It was the weakness of tributary states in Europe, itself the consequence of European peripheralization after the fall of Rome, that allowed capitalist accumulation to become so strong. The Muslim blockage of trade with the East created reactive cultural solidarity among European Christian elites during the time of the Crusades. This facilitated the emergence of a politically multicentric interstate system and allowed for a relatively greater degree of market-based international interaction. When the blockade was broken, merchants, bankers, and commodity producers emerged as important players in cities and states, and they rebuilt a regional economy that embodied commodified exchange and production much more thoroughly than any other region had.

China is the important case for comparison. A similarly strong emergence of markets, money, and commodity production during the Sung dynasty in the tenth century C.E. was eventually suppressed by the strong tributary state of the Mandarins. The absence of such a centralized tributary empire in Europe allowed capitalists and capitalism to gain a strong hold on political power.

What was Europe's position in the core/periphery structures of the larger Afroeurasian system? We need to ask this question for each level of network - BGM, PMN, PGN, and IN - and we need to consider both core/periphery differentiation and core/periphery hierarchy. Regarding the bulk-goods network, Europe was temporarily disconnected from West Asia during the Muslim blockade. The feuda manorial economy was based on local self-subsistence. Thus there was no larger division of labor in bulk goods during this period. When these connections reemerged Europe had developed agricultural production that was nearly as productive as agriculture in the West Asian empires. However, European cities did not become as large as the capital cities of the Near East until the eighteenth century - not because o less productive agriculture, but because of the smaller and less centralized states.

In the Central political/military network, Europe was in a peripheral position after the fall of western Rome and the rise of Islam. Strong West Asian states expanded into Europe, and weak European states were conquered, dominated, an sometimes forced to pay tribute to the West Asian core states. Thus there was a politicaal-military core/periphery hierarchy, and Europe was in the periphery.

With regard to the Afroeurasian prestige-goods net, Europe was almost discor nected during the Muslim blockade, and this disconnection reflected its periphen position in the PMN. After the blockade was broken, Europe rose to semiperipher; status in the Central PMN with the rise of more powerful European states. But whi was Europe's position in the larger Afroeurasian PGN after the fall of the blockade? Janet Abu-Lughod (1987, 1989) and Samir Amin (1991) have portrayed the enchange of prestige goods among European, West Asian, Indie, and East Asian core regions as equal exchange in the world-system of the thirteenth century.

Gunder Frank (1994) has argued that Europe remained in a peripheral relationship with China long after the formation of a regional core in Europe. This contention supported by the nature of the goods exchanged and the efforts of the players in different regions to find alternatives to this trade. As Jane Schneider (1977) has note Europe was importing Chinese manufactures in exchange for bullion. Chinese pore lain and silks were the main products that Europeans desired. Europeans search long and hard to find substitutes less costly than silver and gold to trade for Chine goods. American ginseng and Indian opium are famous examples. Both Europes and West Asian states also engaged in import substitution in order to avoid the cost trade with China and to make profits by selling to other nearby buyers. Sassanid in expanded the production of silk in the seventeenth century (Foran 1993), and d porcelain industry was established in Lower Saxony in the eighteenth century. Indeed European imports of Indian cotton textiles were a major spur to the development industrial cotton textile manufacturing in the English midlands in the eighteen century, another case of "import-substitution-industrialization."

These substitutions support the notion that the long-distance trade with Chii was one of unequal exchange in which the Chinese were gaining greater rerun Frank contends that China was the core of the Afroeurasian world-system. If the ( change had been equal the Europeans and the West Asian states would not ha tried so hard to change the terms. But if this was indeed unequal exchange, what w its basis? It was certainly not due to Chinas exercise of political/military power 01 its distant customers. Though European states would later exploit peripheral regions by using political/military coercion to extract surplus product, China did not project military coercion across Afroeurasia. Rather, the unequal exchange was primarily due to Chinese economic and technological superiority. China could produce highly valued goods and sell them for high prices because the Westerners had no alternative sources of supply (Wolf 1982). The unequal exchange between Europe and China was based on "technological rent."

As we saw in Chapter 8, there was a long and complex history of information flows throughout Eurasia. For at least two millennia, ideas, ideologies, and information have moved back and forth across the landmass. The preponderance of movement has been from east to west. The compass, gunpowder, paper money, and even the stirrup, among many other things, came to Europe from the east. European attempts to "sell" their ideologies, especially Christianity, in the east were dismal failures. Even at the level of the information net, then, the exchange was unequal and was a further motivation for European exploration. Still, these exchanges did not form a basis for domination or exploitation. China was not seeking this trade, the Europeans were. In short, there was core/periphery differentiation, but not core/ periphery hierarchy.

Hence European peripherality had two forms: political/military weakness with respect to the West Asian core states, and technological backwardness relative to some industries in China and India. Both of these conditions spurred Europeans to develop a new form of the relationship between political and economic power - a combination of the strategy of semiperipheral marcher states and semiperipheral capitalist city-states. European arms and naval power underwent rapid technological development because of the extremely competitive relationships among the European states themselves. Further, European capitalism was able to improve upon earlier institutional inventions - money, credit, contract law, private property, wage labor - because the logic of tributary accumulation was relatively weak. In this sense European hegemony was another case of semiperipheral innovation and upward mobility, but this time it was an entire regional core that eventually came to dominate the other core regions of the Afroeurasian system.

What docs our comparative approach tells us about the structural similarities and differences between the modern world-system and earlier regional world-systems? Our comparative perspective has abstracted from scale in order to observe structural similarities and differences, but differences of scale may be important in their own right. The modern world-system now includes all continents and all peoples - a vastly increased number of people because of the rapid population growth in the past few centuries.

Do population size and territorial scale matter for the processes of social reproduction and change that are of focal importance for social science? Braudel (1975) spoke of the thirty-day world as an important limit on long-distance economic exchange relationships. By this Braudel meant that transportation and communications technology limits the size of a system to those regions that can be reached within thirty days. By this criterion the global world-system is far "smaller" than the intercontinental networks of the eighteenth and nineteenth centuries. New transportation and communications technologies have integrated the contemporary system much more tightly than were earlier systems.

What about population size? Does it matter for the logic of social structures whether or not a system contains 10,000 people (as northern California did) or 5 billion? Some . have contended that normative regulation requires face-to-face interaction. If this is true, the number of people that can be integrated by normative regulation is necessarily few. Political/military integration requires only the knowledge of sanctions, and market integration requires only the knowledge of prices. That is allegedly why these modes are much better for integrating large numbers of people. There may be some truth to these assertions. But the development of mass media as well as new (and cheaper) forms of communication has undoubtedly decreased whatever scale advantages market and political/military integration have over normative integration.

We will now apply the model of iterations (see Chapter 6) to the contemporary global world-system. In Chapter 10 we will consider the relevance of the iteration model to the emergence of predominant capitalism in the Afroeurasian system. The iteration model involves population growth, environmental degradation, population pressure, emigration, circumscription, conflict, hierarchy formation, intensification, and further population growth (see Figure 6.1). Most of these terms are the same ones we use to describe the modern world-system, except for intensification. Intensification refers to changes in the technology of production that involve greater efficiencies in the use of labor, land, or other scarce resources.

Rapidly growing population density on all continents constrains the possibilities for emigration as an alternative to new structural innovations. The last frontiers - Antarctica, the seabeds, deserts, and outer space - are costly environments that may yield some resources but almost certainly will not sustain new large populations economically. This means that both environmental and social circumscription are even more important contextual stimulants to transformation in the modern system than they have been in earlier regional systems.

Furthermore, though some tributary states (such as Rome) needed to expand in order to survive, capitalism intensifies this systemic feature to a new level. The realization problem is the need to expand markets in order to realize the profits of more and more commodity production. Capitalism handles this by geographical expansion, by commodifying more and more aspects of life, and by paying some workers more so that they can purchase additional products. Geographical expansion of the capitalist system has reached global limits. Commodification and Keynesiamsm sail have room for expansion. But these eventually will constrain capitalist expansion, which in turn will exacerbate further the contradictions of capitalism.

Environmental degradation continues to push new technological innovations and to exacerbate population pressure. We have already argued that the spatial scale of environmental degradation increases with the size of the system. Once the system has become global the possibilities of escape from ecological ruin are greatly reduced. Global industrial development wrecks the environment on a global scale, whereas earlier intensification wrecked it on a more local or regional scale.

Since the modern system is global, it is even more circumscribed than earlier systems were. Most earlier systems could expand spatially in order to resolve internal contradictions. Most contained more than one noncontiguous core region. We contend that the modern world-system has only one core because the interactions among geographically distant core states are much denser and involve a single global BGN. Thus a possible future rise to hegemony of the northeast Asian region would be an instance of mobility occurring within a single global core rather than the rise of a new unconnected core region. This is very different from the kind of leapfrogging development that occurred in earlier systems. Circumscription constrains the modern world-system to solve its contradictions within itself.

Multisiate systems are not unique to the modern system. Indeed, all the earlier state-based PMNs contained more than one state in their core regions. But the modern system is different in its average degree of political decentralization in the core. The difference between the earlier oscillation between interstate systems and "universal states" and the modern rise and fall of hegemonic core powers is one of the most important qualitative changes that differentiate the modern world-system from earlier state-based systems.

The continuing stability of the interstate system in the Europe-centered world-system is based primarily on the effects that the institutions of capitalism have on the process of the rise and fall of hegemonic core powers. Capitalist commodity production allows owners of capital to accumulate wealth by the production and sale of commodities. This form of accumulation has different implications for the activities of states than does the tributary mode of accumulation, in which political organization itself was the most central institution that facilitated accumulation. In societies dominated by the tributary mode, the state and state-enforced monopolies and relations of production (serfdom, slavery, helorry, etc.) are used to gather tribute and/or taxes. If markets and commodity production existed, they were usually articulated with and dominated by the logic of political competition and state-based coercion. Success in such a system goes to those who are best able to organize institutions of political power and coercion.

Real capitalism has not been a system in which state power is abolished or in which states never interfere with market forces. Rather, it is a system in which the most successful competitors use state power to facilitate capitalist accumulation. This does not mean that taxation and tribute are abolished but rather that they are utilized to support the search for profit-making opportunities in the world market. The capitalist state is not a state that is uniformly controlled by capitalists, nor is it a state that never interferes with market forces. The most successful states, those that have become hegemons, often use state-based coercion both to reproduce the institutional basis for capitalist accumulation and to extend the opportunities of national capitalists to make profits abroad.

The "ideal" of the laissez-faire state has never existed except as a political ideology that one group of capitalists has used against an older group with more state-supported privileges. Even the most successful capitalist states have systematically used state power to create and sustain conditions for profitable accumulation. Free trade is the ideology of successful hegemonic powers who have a significant comparative advantage in production costs. But to get to that position every upwardly mobile country has engaged in protection of those strategic industrial sectors that would otherwise perish from the competition of imports.

We do not contend that every state in the Europe-centered world-economy has been a capitalist state. Rather, we argue that the logic of capitalist accumulation has become increasingly significant as a determinant of state policy and that the most successful states have been the ones that have bent state power to the purposes of gain through production, trade, and finance. A relevant distinction that is often made in histories of the European interstate system is that between states that pursued a "continental" policy and states that pursued a "maritime" policy (Fox 1971, 1991). Thus Venice, Portugal, the Netherlands, and Britain are said to have used their naval power at the behest of international trade, whereas the Hapsburgs, France, and Germany often engaged in a policy of attempting to conquer neighboring territory. The "continental" strategy can in some ways be understood as a throw back to the tributary mode of accumulation, an approach that was successful in transforming many precapitalist systems into corewide empires.

The most successful states in the modern system have not tried to create a corewide empire. This is a major difference from precapitalist systems that requires explanation. The three hegemons (the Netherlands, the United Kingdom, and the United States) have acted to support and maintain the interstate system, even during their periods of decline. The challenges to the interstate system have come from certain other upwardly mobile states trying to aggrandize their standing by taking over other core states.

Why are the strongest states in the modern world-system - the hegemons - uninterested in conquering other core states? Part of the reason is that these are the most capitalist states in the sense that the ruling classes that control them gain and sustain their wealth primarily through commodity production. Freedom of trade and the ability to move capital from less profitable to more profitable investments are very important to capitalists. The interstate system allows for capital mobility and prevents a centralized global state from exerting political control over investment decisions. The interstate system is thus a necessary structural basis for the capitalist mode I of accumulation (Chase-Dunn 1989).

It is not hard to understand why a rising hegemon supports the interstate system, but what about a declining one? Why is it that a declining hegemon that still has a preponderance of military power is not tempted toward corewide empire building when other core powers are gaining a competitive advantage in production? Indeed, a number of observers have noted that declining hegemons do try to prop up their position by expending more resources on arms, a response that often simply exacerbates their economic decline (Thompson 1988; Goldstein 1988; Kennedy 1988). But a military buildup is not necessarily an effort to conquer other core states. It is striking that no modem hegemon has ever undertaken a course toward direct global rule, despite the opportunities that existed following world wars in which more aggressive states have been defeated.

The most important reason for the lack of interest shown by declining hegemons toward corewide empire is that the institutions of international capital investment often make it possible for the dominant capitalist groups within declining hegemons to spread their capital into regions that have higher races of profit. These "international" capitalists then no longer have such a vested interest in the home economy. But they have a strong interest in maintaining the multicentric interstate system. This also is part of the explanation for the vacillation of declining hegemons on tariff protection and a rationalized national industrial policy. With their capital now invested where profits are higher, in other states and in international finance, the capitalists within the hegemon are uninterested in either world political domination or costly efforts to rehabilitate the declining national economy of the hegemonic state. This is one of the main reasons that hegemonic decline is not reversible.

Regarding conflict, warfare occurs almost constantly in the modern interstate system, but there is a fifty-year rise and fall of the severity of wars among core states (Goldstein 1988). Rather than occurring during periods of economic stagnation, the most intense period of core war usually occurs near the end of a period of relatively rapid economic growth when states have greater resources available for war making. World wars are the arbiters of hegemonic transition, as they were in earlier state-based systems. During periods in which there is a strong hegemonic core power there tend to be fewer and less intense wars, a state of affairs called "hegemonic stability."

The discussion of intensification in the iteration model refers to the invention and implementation of new technologies of production. There is general agreement that capitalism revolutionizes technology much more quickly than state-based systems because it provides strong incentives for producers to produce more efficiently. When price competition is an important determinant of production costs and the final price of a product, an entrepreneur who can produce and sell that product more cheaply will take a larger share of the market. But we know that the conditions of pure price competition are actually somewhat atypical within "real" capitalism. Monopoly and oligopoly are much more often found in both input and final goods markets. Yet capitalism indisputably does revolutionize technology much more rapidly than did earlier modes of accumulation, and the rate of technological change has itself changed radically over the past 400 years. Why is this so?

First, die idea of incentives to producers does operate to a greater extent than it did in earlier systems. Despite a number of non-market influences on prices, the operation of market forces in the modern world-system is indisputably much greater than in earlier systems. Though the "competitive sector" of small firms is usually less than one-half of the economy, it serves as an important source of motivation for individuals and firms. The idea that you can get rich by inventing a better mouse trap undoubtedly stimulates a great deal of innovation even if it is rarely the inventors themselves who are the big winners on better mouse traps.

Monopoly capitalism continues to revolutionize technology because even though market regulation of prices is weak, large companies compete for market shares by introducing new products and variations on old ones. This competition through product innovation is a major force behind large expenditures on research and development.

The Weberians see capitalist development as a general process of rationalization and bureaucratization. Capitalism develops forms of calculation such as capital accounting that make it possible to determine much more precisely the profitability of different activities. This encourages technological change because it improves the ability to calculate efficiency and to evaluate alternative methods of production. The problem with this approach is that it equates the rather peculiar social, political, and economic institutions that have historically caused industrialization with a timeless "rationality." It relegates claims about the injustices that have accompanied these institutions to "irrational" or "primordial" concerns about values. Weber and most Weberians assume that rationality works best when it is undertaken by individuals or firms seeking to maximize their own returns. The identification of capitalism with rationality and the equating of collective needs or claims of injustice with irrationality is a much too convenient support for the conclusion that capitalism is the best of all possible worlds. If collective interests are incalculable and democratic planning is impossible, then the best that can be done is to allow people to vote with their dollars. Never mind that so many have so few of these votes.

The political structure of global capitalism - the interstate system - does not guarantee monopolies at the level of the world market. The world market is very dynamic and competitive in almost all industries despite the existence of oligopolies within states. States as well as firms are competitors for world market shares, and states arc increasingly becoming major investors in research and development of new technologies for the production of goods for the world market.

What is new about this is the direct involvement of states in the development of new products for sale. Much older is state sponsorship of military research and development. As Charles Tilly (1990) has so persuasively shown for the European states, states made war and war made states. Military technology has been changing for 2 million years, but a geometric increase in the destructiveness of weaponry has accompanied capitalist industrialization. William McNeill (1982) argues that this is because industrialization produces more wealth, and thus states have more resources, and so they do what they have always done (arm and make war), but now on the larger scale that has been made possible by industrialization.

Capitalist industrialization has resulted in a number of social trends that have greatly increased the rate of technological change. Some of these have been due both to the ways in which people have resisted capitalist development and to the will of capitalists themselves. Mass education is an important structural basis of technological innovation. State expenditures on mass education have developed in response to the needs of capitalists for skilled workers and the demands of citizens to acquire marketable skills. The consumerist culture of capitalist societies is a major mechanism for integrating middle classes into the capitalist "success story." The expansion of mass consumption has been the partial result of the "realization problem" by which capitalists need effective demand for the commodities they produce, and. the partial result of political class struggles in which certain groups of primary sector and middle-class workers have obtained higher incomes, especially in core societies.

This kind of income redistribution in core countries has spurred technological change in consumer industries as firms compete for market shares through product innovation and built-in obsolescence. This kind of technological revolution is only "efficient" (and profitable) as long as environmental costs are externalized. This in turn depends on the maintenance of an appropriate political structure. While many of the problems created by this kind of consumption are global in extent, the interstate system and the core/periphery hierarchy make coordinated solutions difficult.

Capitalism not only provides the resources for vast core-state expenditures on military technology (and reinforces the structural need for military competition), but it also produces resources for the expansion of technical and scientific pursuits. Such expenditures obviously spur technological innovation and play an important role in the competition among core firms and states for shares of the world market. The "Japan Incorporated" model - in which state expenditures on education and science are coordinated with a national industrial policy designed to capture a large share of the future world market for the most profitable commodities - has become the exemplar of rational state capitalism.

"Intensification" often leads to a new round of population growth, and this begins another revolution of the iteration wheel. In the modern world-system the relationship also works this way, but it is complicated by what has become known as the demographic revolution. In the most developed countries the birth rate has declined because parents have been able to provide for their children without requiring the children to do immediately productive work. The shift toward a labor-free childhood has caused children to become economically costly to parents, and so the number of children that each couple bears has decreased. In less developed countries, where the shift to a culture of non-working children has not taken hold, children continue to be an economic asset, and so the number of children in each family remains high.

Public health measures have lowered mortality rates. The consequent population explosion in peripheral and semipenpheral countries, is well known. In d long-run comparative perspective it is the periphery that illustrates the typical relationship between technological change and population growth, whereas the demographic revolution in the core is unique, at least in its extent. But since the majority of the population remains in non-core countries, the overall result is that the global population is rising, and this is leading to many of the consequences that population growth has led to in the past - pressure on natural resources, pressures for migration, and circumscription. The rapid increases in agricultural productivity over the past 100 years have allowed food production more or less to keep pace with rapid population expansion, but many observers (e.g.. Meadows, Meadows, and Randers 1992; World-watch 1994) doubt that the rate of increase in agricultural productivity can be sustained for many more decades. Thus the classical force of population pressure on food supplies is likely to visit the modern world-system with the same general patterns that earlier systems experienced - conflict and pressure for a new form of hierarchy formation.

Before we further examine possible futures, we will shift from case studies to a formal comparison of world-systems and our tentative conclusions regarding the problem of systemic transformations.