30: Sumer—The First Agrarian Civilization2600 B.C.E., known as the Standard of Ur, depicts the army of Ur, with its donkey-drawn chariots and large convoys of captives.Inspiring awe by lavish displays of power was one of the keys to statehood. The royal tombs of Ur, from the late 4th millennium B.C.E., show the spectacular riches rulers could accumulate and the extraordinary expense lavished on tombs, temples, and palaces. As in the royal burials of many early Agrarian civilizations, servants of the ruler were often killed and buried to serve in the afterlife. From late in the 3rd millennium B.C.E., the typical form of monumental architecture in Mesopotamia would become the ziggurat, a stepped pyramid-like temple dedicated to the gods, of which the best preserved today is that of Ur.Two more signi¿ cant changes occurred about 1,000 years after the appearance of the ¿ rst states. Sumer’s city-states were united under a single ruler, Sargon, who ruled from c. 2370 to 2316 B.C.E. from a city called Akkad in northern Sumer. This pattern of imperial expansion would recur many times in later Agrarian civilizations. In the centuries after Sargon, Sumer’s population crashed, apparently as a result of over-irrigation, which led to salination and undermined the region’s fertility. This pattern, too, would recur many times in the history of Agrarian civilizations.Voilà! A whole series of linked features came together to establish the ¿ rst tribute-taking city-states in ancient Sumer. In the next lecture we ask: How similar was the process of state formation in other early Agrarian civilizations? ŶChristian, Maps of Time, chap. 9.Fagan, People of the Earth, chap. 15.Ristvet, In the Beginning, chap. 4. Essential Reading
141Fernandez-Armesto, The World, chap. 3.Nissen, The Early History of the Ancient Near East.Trigger, Early Civilizations.1. What were the most important “emergent properties” of the earliest Agrarian civilizations?2. What were the crucial preconditions for the appearance of the ¿ rst tribute-taking states about 5,000 years ago? Supplementary Reading Questions to Consider
31: Agrarian Civilizations in Other RegionsAgrarian Civilizations in Other Regions
31The Nile was a wonderful river along which to trade. Trade winds heading south and river currents heading north made sailing up and down the river relatively easy. And we know that Egyptian rulers sent expeditions for ivory and gold, for example, to Nubia and Punt, in modern Ethiopia, and also to Lebanon for its famous cedars. We still have ¿ ne illustrations of a À eet that was sent by Hatshepsut—one of the few female pharaohs, who ruled soon after 1500 B.C.E.How typical was Sumer of Agrarian civilizations in general? Agrarian civilizations were constructed using the huge human and material resources generated in regions of À ourishing agriculture, so each civilization was shaped to some degree by the cultural traditions and ecology of the regions in which it emerged. This lecture brieÀ y surveys six different areas in which Agrarian civilizations appeared early. The main exception to the general rule that agriculture generated civilizations is in tropical areas such as Papua New Guinea (and perhaps the Amazon basin). Here, agriculture may have appeared early, but it was based on root crops that could not be stored for long periods. As William McNeill argues, the lack of storable wealth may explain why these regions never supported Agrarian civilizations.Within the Afro-Eurasian world zone, Agrarian civilizations emerged along fertile river systems in four different regions. We have seen how Sumerian civilization arose in the Euphrates-Tigris basin, in the form of a cluster of competing city-states all dependent on irrigation. Nearby, in modern Sudan and Egypt, an Agrarian civilization appeared at about the same time, based on the remarkable natural irrigation system of the Nile River. The annual À oods of the Nile, the world’s longest river, brought nutritious silts from the south. After about 5000 B.C.E., the Sahara desert became drier, and more people settled in the Nile Valley. As in Sumer, populations grew rapidly, but here most settled in a long ribbon of villages along the Nile. Wheat and barley, introduced from Mesopotamia around 5000 B.C.E., À ourished.
143So did watermelons and other crops from Sudan. By 4000 B.C.E., village communities stretched from the Nile Delta to Nubia, in modern Sudan.Small kingdoms appeared and were rapidly united within a single large state. Around 3100 B.C.E., a southern ruler called Menes (or Narmer) uni¿ ed the region north of Aswan into a single empire. The Narmer Palette, probably engraved by a contemporary, shows the pharaoh smiting his enemies. Cities were less important than in Mesopotamia, though Menes established a capital at Memphis, south of modern Cairo. Unlike the rulers of Sumer, who were either priests or kings, Egypt’s “pharaohs” were treated as gods. Their tombs, the pyramids, reÀ ect their high status. The largest, the pyramid of Cheops, was built between 2500 and 2600 B.C.E., using 2.3 million limestone blocks. Despite occasional periods of political breakdown, Egyptian dynasties ruled the Nile region for almost 2,600 years. The regularity of the Nile À oods may explain why Egyptian civilization avoided the sort of ecological collapse experienced in many other early Agrarian civilizations. A hieroglyphic writing system developed early here, possibly under indirect Mesopotamian inÀ uence. Trade winds heading south and river currents heading north encouraged trade along the Nile. Egyptian rulers sent expeditions for ivory and gold to Nubia and Punt and for timber to Lebanon. We still have ¿ ne illustrations of a À eet sent by Hatshepsut. Early in the 3rd millennium, cities and states appeared in the north of modern Pakistan and India. The Indus river brought rich Himalayan silts but À ooded less predictably than the Nile. By 2500 B.C.E., there were many small towns and at least two huge cities, now known as Harappa and Mohenjo Daro. Each had about 40,000 inhabitants. Houses and streets were built along a carefully planned grid system using prefabricated bricks. There were water and sewage systems, uniform systems of weights and measures, specialized crafts, markets, and extensive trade with Mesopotamia and Central Asia. Here, too, a writing system evolved. Unfortunately, it has not yet been deciphered, so our knowledge of this civilization depends entirely on archaeology. The The annual À oods of the Nile, the world’s longest river, brought nutritious silts from the south.
31: Agrarian Civilizations in Other Regionsabsence of obvious palaces or royal tombs limits our understanding of the political system. The Indus Valley civilization collapsed early in the 2nd millennium. Overpopulation may have caused ecological collapse through deforestation, erosion, À ooding, and deserti¿ cation.The earliest Agrarian civilizations in China emerged along the Yellow River, whose fertile “loess” soils formed from dust blown in from Inner Asia. Agriculture was productive, but À ooding was a perennial problem. Chinese traditions describe two ancient dynasties, the Xia and Shang. Cities and states appeared along the eastern Yellow River late in the 3rd millennium. The Xia dynasty was probably one of several regional kingdoms. Its capital, at Erlitou, has been recently excavated. The Shang dynasty ruled for much of the 2nd millennium B.C.E. Bronze metallurgy and horse-drawn chariots, as well as wheat and barley, may have arrived from the West. The Shang controlled many cities. They had large armies equipped with mass-produced weapons and armor, and they built massive royal tombs and palaces. There may have been other similar kingdoms in other regions of China. Shang writing, using symbols carved on tortoise shells or other bones, can still be read today. Here, writing was linked to divination, a skill highly valued in rulers. Rituals were important, but deities and priests played a smaller role than in Mesopotamia or Egypt.Agrarian civilizations appeared later, but quite independently, in two regions in the Americas. We will survey these civilizations in more detail in
Thirty-Seven. “Mesoamerica” includes southern Mexico and parts of Central America. The ¿ rst incipient civilizations appeared among the “Olmec” during the 2nd millennium B.C.E. In the 1st millennium, cities and states also appeared in the Oaxaca valley, in modern Mexico. By the 1st millennium C.E., there were cities and states throughout Mesoamerica. Here, great river valleys played a lesser role than in Afro-Eurasia, though techniques for increasing agricultural productivity included forest clearance and the creation of large arti¿ cial swamplands. In the Andes, state systems emerged in the 1st millennium B.C.E. along the arid coasts of Peru (where they relied largely on ¿ shing) and in the Andean uplands around Lake Titicaca (which relied on maize, potato, and quinoa). Exchanges of crops and other goods between lowland and upland regions laid the foundations for the ¿ rst large empires.
145The Inka Empire, which À ourished in the 15th and early 16th centuries C.E., was the ¿ rst to link these centers into a single political system.This brief tour of some of the earliest Agrarian civilizations hints at their variety. But there were also some remarkable similarities, which we return to in the next lecture. ŶBentley and Ziegler, Traditions and Encounters, chaps. 3–6.Christian, Maps of Time, chap. 9.Fagan, People of the Earth, chaps. 15–18, 21, 22.Brown, Big History, chap. 6.Fernandez-Armesto, The World, chap. 4.Mann, 1491.1. What were the most important differences between the earliest regions of Agrarian civilization?2. How important was religion in the appearance of Agrarian civilizations? Essential Reading Supplementary Reading Questions to Consider
32: The World That Agrarian Civilizations MadeThe World That Agrarian Civilizations Made
32So, the many striking similarities between Agrarian civilizations, even where there were no signi¿ cant contacts, count as one of the most interesting and important factors about human history because they provide powerful reasons for thinking that human history is in some sense directional—that it was shaped by large, general factors that you could only see if you look at human history on a large scale.Why were all Agrarian civilizations so similar despite the limited contact between them? Why did human societies in different parts of the world not evolve in utterly different ways? The fact that they did not suggests that there are large forces, perhaps related to our astonishing adaptability as a species, that drive human history in particular directions despite local differences in geography and cultural traditions. It is tempting to think that, ultimately, those similarities derive from the human capacity for collective learning, which ensured that, over time, human societies—wherever they might appear—would acquire increasing resources that would allow the appearance of larger and more complex societies. In short, it may be collective learning, the de¿ ning feature of our species, that helps explain the apparent directionality of human history. This lecture concentrates on general features of the 4,000-year era dominated by Agrarian civilizations. Instead of discussing each civilization in turn, we will discuss Agrarian civilization in general. As Robert Wright puts it, “if we relax our vision, and let these details go fuzzy, then a larger picture comes into focus: As the centuries À y by, civilizations may come and go, but civilization À ourishes, growing in scope and complexity” (Christian, Maps of Time, p. 283).Though labels for eras and types of societies are arti¿ cial, we need them because to understand the past we have to break it into manageable chunks. Chronologically, we will use two interchangeable labels for the epoch from 3000 B.C.E. to about 1000 C.E.: the “later Agrarian” era and the “era of Agrarian civilizations.” This epoch was dominated by Agrarian civilizations.
147Spatially, it is helpful to divide the world before modern times into four separate world zones. The Afro-Eurasian world zone includes the African and Eurasian continents and offshore islands such as Britain and Japan. It was the most ancient zone because this is where humans evolved. It was also the largest and most varied world zone, which may explain its dominant role in world history. It was where agriculture and Agrarian civilizations ¿ rst appeared. The American world zone was the second-largest world zone, though it was settled late, probably within the last 13,000 to 15,000 years. This was the second zone in which Agrarian civilizations evolved independently. The Australasian world zone includes modern Australia and Papua New Guinea, as well as offshore islands such as Tasmania. Though agriculture did appear in Papua New Guinea, Agrarian civilizations did not evolve independently in this world zone. The Paci¿ c zone was settled within the last 4,000 years by seafaring communities from Southeast Asia, who brought agriculture with them. Here, some elements of Agrarian civilizations did appear by diffusion on some of the larger islands such as Hawaii. But no island was large enough to support large Agrarian civilizations.Not everyone lived within Agrarian civilizations even in the era of Agrarian civilizations. Beyond their borders were regions inhabited by peoples regarded, at least by the rulers of Agrarian civilizations, as “barbarians.” In some regions, such as Australia, most people continued to live in foraging communities like those of the Paleolithic era, and many lived in such communities until the 20th century. Many people lived in small farming communities with rudimentary political structures like the villages of the early Agrarian era. In arid regions of Afro-Eurasia, there were communities of pastoral nomads, some of which, like the Mongols, posed serious threats to neighboring Agrarian civilizations. Finally, there appeared the Agrarian civilizations that are the main subject of this lecture. This list provides a rudimentary, four-part typology of pre-modern human societies that reminds us of the great variety of adaptations developed by our species.At the core of all Agrarian civilizations were tribute-taking states. States exacted resources in labor, goods, or cash.
32: The World That Agrarian Civilizations MadeNow we focus on some of the shared features of the largest and newest of these communities: Agrarian civilizations. Agrarian civilizations were huge and complex, with hundreds of thousands, or millions, of inhabitants linked by religion, trade, economics, and politics. They were supported by the surplus labor and produce of peasant farmers, who made up most of the population. (As a rule of thumb, in most Agrarian civilizations, it took about nine peasants to support one city dweller.) Peasant life was tough. Egyptian documents from late in the 2nd millennium B.C.E. provide a vivid description of peasant life and the many trials caused both by natural disasters and the demands of tribute-takers. Elite groups, particularly in towns and cities, supported themselves by exchanging specialist skills as artisans, traders, warriors, priests, and rulers.At the core of all Agrarian civilizations were tribute-taking states. States exacted resources in labor, goods, or cash. Tributary rulers claimed the right to exact resources but backed up their claims with the threat of force. We call such exactions “tributes.” Their coercive power depended on organized armies that could defend against external attacks and suppress internal resistance. Administrative tasks, such as the collection and storage of tributes, or the administration of justice and law, were handled by organized groups of literate of¿ cials. The documents we have used earlier in this lecture provide a vivid account of the attractions of being a scribe and of¿ cial. Writing appears in all Agrarian civilizations, though in some cases (e.g., the Inka), it assumed rudimentary forms. Tributary rulers built “monumental architecture”: tombs, palaces, and temples designed to display their majesty and power. At lower levels, rulers depended on local nobles or of¿ cials, who duplicated their power on smaller scales.Within Agrarian civilizations there were steep, and relatively rigid, hierarchies of wealth and power. Class hierarchies ranked groups by their lineage and social status. Aristocracies were distinguished by their lineage, power, lifestyle, and wealth. Members of the ruling elites generally despised the peasants who generated most of society’s wealth. They also tended to regard those outside Agrarian civilizations as inferior or subhuman. And they normally despised merchants, whose wealth came not from tributes but from entrepreneurial activity. Power hierarchies shaped gender hierarchies. As most rulers were men, women rulers were generally regarded as exceptional
149(which is why the Pharaoh Hatshepsut is often represented wearing a fake beard). However, women often ruled indirectly, through husbands, lovers, or fathers. And women rarely lacked rights entirely. The oldest surviving legal code, compiled by Mesopotamian emperor Hammurabi (who reigned circa 1792–1750 B.C.E.), recognizes their right to divorce abusive husbands.This lecture has surveyed some general features of Agrarian civilizations. In the next lecture, we ask: How did Agrarian civilizations change during the 4,000 years after their ¿ rst appearance? ŶChristian, Maps of Time, chap. 10.Ristvet, In the Beginning, chap. 4.Ehrenberg, Women in Prehistory.Trigger, Early Civilizations. 1. Did Agrarian civilizations share enough features to justify treating them as a major “type” of human community?2. Of all the features shared by Agrarian civilizations, which do you regard as the most important? Essential Reading Supplementary Reading Questions to Consider
33: Long Trends—Expansion and State PowerLong Trends—Expansion and State Power
33By 5,000 years ago, by 3000 B.C.E., there were probably about 50 million people on Earth. Now, what this means is that in the early Agrarian era, human populations had multiplied by about 10 times. Then by 1,000 years ago, at the end of the later Agrarian era, there may have been about 250 million people on Earth.The previous lecture described some general features of Agrarian civilizations. The next three lectures ask: How did Agrarian civilizations change during the 4,000 years of the later Agrarian era? They focus on Afro-Eurasia, the largest and most inÀ uential of the four world zones. This lecture describes two ways in which Agrarian civilizations in Afro-Eurasia expanded during almost 4,000 years. First, Agrarian civilizations occupied larger areas and incorporated more people. Second, as rulers got more skillful at their craft, and knowledge of “governance” accumulated within elite groups, the power and reach of states increased.In the course of 4,000 years, Agrarian civilizations spread to incorporate most of the population of the Afro-Eurasian world zone. Five thousand years ago (in 3000 B.C.E.), Agrarian civilization existed only in Sumer and Egypt. Four thousand years ago (in 2000 B.C.E.), Agrarian civilizations also existed in the north of the Indian subcontinent and along the Yellow River in northern China. By 2,000 years ago, Agrarian civilizations were also À ourishing around the Mediterranean basin, in southern China, and in parts of Southeast Asia. By 1,000 years ago, Agrarian civilizations had spread to sub-Saharan Africa, and to both western and eastern Europe.Estonian American scholar Rein Taagepera has tried to quantify these changes by estimating the areas included within states in “megameters.” A megameter is approximately the size of modern Egypt. Though very approximate, these calculations do seem to indicate some clear trends. In 3000 B.C.E., states controlled just 0.2 megameters, which is almost 0.2% of the area of Afro-Eurasia that is controlled by modern states. (Today, of course, states control virtually the entire landmass of Afro-Eurasia, so this is a reminder of how
151exotic and unusual the ¿ rst Agrarian civilizations were when they appeared.) In 1000 B.C.E., Agrarian civilizations controlled almost 2.5 megameters (about 2% of the area of Afro-Eurasia that is controlled by modern states). By 1 C.E., with the appearance of huge empires in Persia, China, and the Mediterranean, Agrarian civilizations covered 8 megameters (about 6% of the area under modern states, and about 40 times the area controlled by the very ¿ rst states). By 1000 C.E., Agrarian civilizations covered about 16 megameters, which is still only about 13% of the area controlled by modern states.What do these ¿ gures suggest? First, they imply population growth. Agrarian civilizations included the most À ourishing and productive regions on Earth, so they were the regions in which populations grew most rapidly, and their growth is therefore a key ingredient in the growth of world populations. Ten thousand years ago there were 5–6 million people on Earth. By 5,000 years ago, there were about 50 million people, so the population had multiplied by about 10 times in the 5,000 years of the early Agrarian era. By 1,000 years ago, there were about 250 million people on Earth, so the population had multiplied by about 5 times in the 4,000 years of the later Agrarian era. These ¿ gures suggest that, though populations continued to grow in the later Agrarian era, they grew no faster than in the early Agrarian era. Taagepera’s ¿ gures also remind us that even quite recently many people in Afro-Eurasia still lived outside Agrarian civilizations, in small communities of pastoralists, foragers, or independent peasants. However, Taagepera’s ¿ gures also chart a fundamental transformation in human history because they suggest that within just 4,000 years most humans on Earth lived within Agrarian civilizations. Agrarian civilizations had become the normal type of community for human beings in Afro-Eurasia (and probably throughout the world).The area under Agrarian civilizations expanded, in part, because tributary rulers learned to control larger areas. In 3000 B.C.E., states were novelties, and their rulers were unsure of the best ways of managing such vast and complex communities. Over 4,000 years, their political, military, and economic skills improved, and so did their reach and power. The basic challenge was to maximize the resources rulers extracted from populations consisting mainly of small-holding peasants. We call resources extracted in
33: Long Trends—Expansion and State Powerthis way “tributes,” to contrast them with “gifts” (which are given freely) and “pro¿ ts” (which are generated through exchanges in competitive markets). The trick was to maximize resource extraction without exhausting the capacity of peasants to keep paying.Roughly speaking, we can track increasing power by charting the increasing size of states. Rein Taagepera has estimated changes in the areas controlled by particular states. His calculations highlight four main eras in the expansion of state power. The ¿ rst city-states covered tiny areas. Uruk covered about 2.5 square kilometers (a tiny fraction of 1 megameter), though its rulers also controlled nearby villages. The ¿ rst Mesopotamian state to include several city-states, that of Sargon of Akkad (2371–2316 B.C.E.), may have controlled 0.6 megameters. In the 2nd millennium B.C.E., the largest states—those of Egypt at its height and Shang China—controlled about 1 megameter of territory, and most controlled much less. So 1 megameter seems to have been a rough upper limit for empires formed before the 1st millennium B.C.E. The Persian Achaemenid Empire, founded by Cyrus II in 560 B.C.E., marks a sudden increase in the size of large states. It covered about 5.5 megameters. For the next 1,500 years, the largest states ranged from about 4 megameters (the Roman Empire) to about 10 megameters (the earliest Islamic empires). In the last 1,500 years, much bigger empires have appeared, starting with the Mongol Empire, which brieÀ y controlled about 24 megameters. These estimates hide eras of collapse and decline, such as the decline of Mesopotamian states early in the 2nd millennium through ecological collapse. Nevertheless, with the bene¿ t of hindsight the long trend toward increasing state power is unmistakable.How did states expand their power and reach? Rulers increased their military authority partly by recruiting larger armies and equipping them with increasingly sophisticated weapons, such as chariots and siege weapons. Some of the more important innovations, particularly in cavalry warfare, came from the pastoral nomads of the Eurasian steppes. Road building and the establishment of courier or post-horse systems allowed rulers to send armies, supplies, and messages over large distances. We have a wonderful description by Herodotus of the Persian “Royal Road” built between 550 and 486 B.C.E. between southern Persia and modern Turkey. As bureaucracies expanded, they became more effective at managing tax collection over large
153areas by supervising the activities of local power brokers. The Achaemenid Empire, for example, set quotas in silver for each of its main provinces, and police spies checked up on tax collection. States also developed subtler ways of mobilizing resources. As their reach increased, states created large zones of relative stability within which peasants and merchants À ourished, so both populations and available resources increased. In such times, the interests of rulers, peasants, and merchants came closest together, and the most farsighted rulers understood that protecting the interests of those they ruled was often the most effective way of generating taxable wealth. Rulers became increasingly adept at using tributes: ¿ rst, to bind the ruling elites together through the sharing of privilege; and second, to overawe their subjects by displays of power such as military triumphs or the building of religious monuments that displayed their closeness to the gods.This lecture has surveyed the spread of Agrarian civilizations and their increasing power over almost 4,000 years. The next lectures will ask about rates of innovation in the later Agrarian era. Did Agrarian civilizations encourage or discourage the capacity for innovation that is such a distinctive feature of our species? ŶBrown, Big History, chaps. 6, 7.Christian, Maps of Time, chap. 10.Taagepera, “Size and Duration of Empires.”For details on particular civilizations, see Bentley and Ziegler, Traditions and Encounters; and Fernandez-Armesto, The World.Rulers increased their military authority partly by recruiting larger armies and equipping them with increasingly sophisticated weapons, such as chariots and siege weapons. Essential Reading Supplementary Reading
33: Long Trends—Expansion and State Power1. What evidence is there that, broadly speaking, the power of tribute-taking states increased in the 4,000 years after the appearance of the ¿ rst states?2. What new techniques and methods enhanced the power and reach of Agrarian states? Questions to Consider
155Long Trends—Rates of Innovation
34One more example [of micro-innovations] may be the slow spread of windmills. We ¿ rst get evidence of them in Persia late in the 1st millennium C.E. And then they start to spread quite widely throughout the Mediterranean, eventually in Europe.By modern standards, change was slow in the era of Agrarian civilizations. So it is all too easy to think of this as an era of stagnation. Yet we have also seen that there was considerable long-term growth in this period, and that suggests that there must have been a continuous trickle of innovations. What factors encouraged innovation in the era of Agrarian civilizations? Earlier lectures argued that collective learning—the ability to share and accumulate learned information—is what makes our species different. Ultimately, collective learning is the source of all innovation in human history. Indeed, collective learning can generate cycles of positive feedback, as innovations allow population growth, which increases the number of people contributing to innovation. But speci¿ c features in each era and region can also accelerate or slow the pace of innovation. This lecture discusses four features of Agrarian civilizations that could stimulate innovation.x Population growth. x Expanding networks of exchange. x Increasing market activity. x The role of states.Danish economist Ester Boserup (1910–1999) argued famously that population growth can stimulate innovation, as those at the edges of society are forced to seek new ways of feeding and supporting themselves. During the 4,000 years of the later Agrarian era, human populations multiplied by about ¿ ve times, growing from about 50 million to about 250 million people.
34: Long Trends—Rates of InnovationFeeding these growing populations depended on a constant trickle of mini-innovations, some of which were almost certainly driven by population pressure. Peasants or their masters sought out new lands to farm and encouraged settlement in new regions. That meant adapting to new soils, climates, and neighbors and adopting new farming techniques and crops. Examples include new crops such as the strains of rye that allowed farmers migrating from eastern Europe to begin settling the lands of modern Russia some 1,500 years ago, or the slow spread of windmills, which are ¿ rst recorded in Persia late in the 1st millennium C.E.The increasing size and variety of exchange networks could also stimulate the spread of innovations. Roughly speaking, the larger and more diverse the networks of exchange, the larger the pool of ideas they contained, and the greater the chances for the spread of signi¿ cant innovations. In the later Agrarian era, the most important large exchange networks were the “silk roads,” which crossed most of the Afro-Eurasian world zone. As early as 4,000 years ago, innovations such as horse-riding and the use of chariots may have diffused from the steppelands to the Mediterranean region and also to China, while Indo-European languages, which probably originated in modern Russia, were spreading toward China, India, and Mesopotamia. Two thousand years ago, trans-Eurasian exchanges became more common. Chinese governments traded with Central Asia, Chinese silks entered Mediterranean markets, and Buddhism traveled from India to China. The travels of Chinese envoy Chang Ch’ien to Central Asia in the reign of Han Emperor Wu-ti (141–87 B.C.E.), or the astonishing military campaigns of Alexander the Great (365–323 B.C.E.), provide vivid illustrations of how Agrarian civilizations from different ends of the Eurasian landmass came into closer contact with each other. Sea trade also increased between the Mediterranean, India, Southeast Asia, and China, as mariners learned to exploit the monsoon winds of the Indian Ocean. By 2,000 years ago, and perhaps earlier, most of Afro-Eurasia belonged to a single “world system.” (The term “world system” is derived from the work of Immanuel Wallerstein Despite their hostility to commerce, tribute-taking rulers could also stimulate innovation and growth.
157and refers to a large region linked within a single network of exchanges.) This meant that goods, ideas, religions, and technologies were now being exchanged across the largest of all the world zones.The expansion of commerce and trade was also a crucial source of innovation. Since Adam Smith (1723–1790), economists have understood that competitive markets encourage innovation. Unlike tributary rulers, merchants lacked the power to generate wealth by force; instead, they had to use ¿ nesse. They had to produce and sell goods as ef¿ ciently and cheaply as possible. That required a constant openness to innovation. This is “Smithian” growth. Tributary rulers normally despised commerce, but they also needed goods such as rare stones or silks, or horses that only merchants could supply, so they often protected commerce. But merchants À ourished best in the cracks between Agrarian empires, such as in small city-states that traded with wealthy neighbors. Venice and Genoa in Renaissance Italy and ancient Phoenicia are good examples of such highly commercial city-states. Urbanization stimulated commerce because cities sucked in goods, techniques, and people from large hinterlands. In 3000 B.C.E., few cities had more than 30,000 inhabitants, and most were in Mesopotamia or Egypt. By 100 C.E., there may have been over 70 large cities spread throughout Afro-Eurasia, some with populations of several hundred thousand (Christian, Maps of Time, p. 326).Despite their hostility to commerce, tribute-taking rulers could also stimulate innovation and growth. Generally, tribute-takers had less incentive to innovate than merchants, because they could extract resources coercively. Indeed, in an era when growth was painfully slow by modern standards, it often made more sense to capture wealth through war, than to produce wealth through investments that could take generations to mature. That is why most rulers in the later Agrarian era thought of themselves primarily as warriors rather than producers. They admired warfare, found ful¿ llment in it, and spent much time preparing for it. Nevertheless, to succeed as tributary rulers, they sometimes had to encourage innovation. Heavy taxation encouraged innovation, as peasants were forced to raise production in order to feed themselves and pay taxes. The most farsighted rulers understood that they could increase tributes by stimulating production and maintaining infrastructure. That meant protecting peasants, building and maintaining