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But demand for locally unobtainable resources was clearly only a part of the story.
Bartering was a basic trade mechanism for many thousands of years; often sporadic and usually based on notions of reciprocity, it involved the mutual exchange of commodities or objects between individuals or groups. Redistribution of these goods through society lay in the hands of chiefs, religious leaders, or kin groups. Such redistribution was a basic element in chiefdoms. The change from redistribution to formal trade-often based on regulated commerce that perhaps involved fixed prices and even currency-was closely tied to growing political and social complexity and hence to the development of the state in the ancient world.
In the 1970s, a number of archaeologists gave trade a primary role in the rise of ancient states. British archaeologist Colin Renfrew attributed the dramatic flowering of the Minoan civilization on Crete and through the Aegean to intensified trading contacts and to the impact of olive and vine cultivation on local communities. As agricultural economies became more diversified and local food supplies could be purchased both locally and over longer distances, a far-reaching economic interdependence resulted.Eventually, this led to redistribution systems for luxuries and basic commodities, systems that were organized and controlled by Minoan rulers from their palaces. As time went on, the self-sufficiency of communities was replaced by mutual dependence. Interest in long-distance trade brought about some cultural homogeneity from trade and gift exchange, and perhaps even led to piracy. Thus, intensified trade and interaction, and the flowering of specialist crafts, in a complex process of positive feedback, led to much more complex societies based on palaces, which were the economic hubs of a new Minoan civilization.
Renfrew's model made some assumptions that are now discounted. For example, he argued that the introduction of domesticated vines and olives allowed a substantial expansion of land under cultivation and helped to power the emergence of complex society. Many archaeologists and paleobotanists now question this view, pointing out that the available evidence for cultivated vines and olives suggests that they were present only in the later Bronze Age. Trade, nevertheless, was probably one of many variables that led to the emergence of palace economies in Minoan Crete.
American archaeologist William Rathje developed a hypothesis that considered an explosion in long-distance exchange a fundamental cause of Mayan civilization in Mesoamerica. He suggested that the lowland Mayan environment was deficient in many vital resources, among them obsidian, salt, stone for grinding maize, and many luxury materials. All these could be obtained from the nearby highlands, from the Valley of Mexico, and from other regions, if the necessary trading networks came into being.Such connections, and the trading expeditions to maintain them, could not be organized by individual villages. The Maya lived in a relatively uniform environment, where every community suffered from the same resource deficiencies. Thus, argued Rathje, long-distance trade networks were organized through local ceremonial centers and their leaders. In time, this organization became a state, and knowledge of its functioning was exportable, as were pottery, tropical bird feathers, specialized stone materials, and other local commodities.
Rathje's hypothesis probably explains part of the complex process of Mayan state formation, but it suffers from the objection that suitable alternative raw materials can be found in the lowlands. It could be, too, that warfare became a competitive response to population growth and to the increasing scarcity of prime agricultural land, and that it played an important role in the emergence of the Mayan states.
Now that we know much more about ancient exchange and commerce, we know that, because no one aspect of trade was an overriding cause of cultural change or evolution in commercial practices, trade can never be looked on as a unifying factor or as a primary agent of ancient civilization. Many ever-changing variables affected ancient trade, among them the demand for goods. There were also the logistics of transportation, the extent of the trading network, and the social and political environment. Intricate market networks channeled supplies along well-defined routes. Authorities at both ends might regulate the profits fed back to the source, providing the incentive for further transactions. There may or may not have been a market organization. Extensive long-distance trade was a consequence rather than a cause of complex societies.