GEOGRAPHIC BASES of trade are places established for the trade or exchange of commodities and/or the transshipment or warehousing of goods. While a base of trade may develop into a multifunctional administrative and/or ceremonial center, its original function as a nodal point at the intersection of at least 2 discreet networks remains the center’s primary reason for existence, until that intersection ceases to be of importance for the trading partners. Scholars of premodern trade (to the early 1800s in industrialized countries) have identified several categories of trading bases, most prominently entrepots or emporia, fairs, solar central places, ports of trade, and gateway communities. While these categories often denote similar sites, they were created by different disciplines to describe the role of the trading base in different disciplinary contexts. Entrepots/emporia and fairs are terms used in historical sources and, therefore, by historians. Entrepots/ emporia were permanent trading bases, located either in a town’s harbor, but physically separated from the town, or as a free-standing colonial trading settlement situated at the border between 2 distinct ethnocultural zones. Both types were permanent bases administered by port officials to collect tariffs and maintain a peaceful and fair trading zone through special laws for foreign merchants. Although entrepots could operate on a seasonal basis, their primary purpose was trade. Fairs, in contrast, were generally of short duration, were held at multifunctional centers, and could move cyclically among several such centers over the course of a year. There were 3 types of fairs, serving local, regional, and interregional trade. Local fairs lasted 1 to 2 days, had a small catchment area (30-mile or 48- kilometer radius), transacted a low volume of goods (cattle and salt), and saw small-scale traders selling directly to the locals. Regional fairs could last up to 2 weeks, had a larger catchment area (up to a 200-mile or 321-kilometer radius), had a higher turnover of goods, and saw merchants buying or selling to specialized producers. Interregional fairs had durations of 3 to 8 weeks, a large catchment area (up to a 600-mile or 965-kilometer radius), and specialized in the sale of luxury items that were carried directly to the fair over long distances. The Champagne fairs of France are the best-known example of a circulating fair, which began as local fairs, grew into regional fairs for Flemish cloth agents, and eventually became Europe’s largest fair circuit for the exchange of cloth and other goods for spices and luxuries brought by Italian merchants from the East. Economic geographers and anthropologists use other categories to explain premodern exchange systems. The solar central place is used by geographers to describe a site that serves as the center of an interlocking system of lower hierarchical centers. Administered by elites, the central place maximized the exchange of goods by shortening the distance between more distantly dispersed centers in the region. While central place theory stresses spatial relationships, the anthropological model of the port of trade, developed by Karl Polanyi, places focus on institutional factors. Ports of trade bordered 2 distinct economic, environmental or ethnocultural zones and operated as “neutrality devices” to facilitate trade between foreign merchants and the host population. Like the entrepot/emporium, a port of trade was founded by a tacit or explicit agreement between foreign traders and the local elites. In order to sustain peaceful trade, however, the long-distance trade occurring at the segregated port of trade could not interfere with the local trade of the hinterland, a criterion that is often impossible to demonstrate with archaeological evidence. In contrast, the geographical gateway community is a more flexible type, describing a trading base that bordered different mineral, agricultural, and/or craft production zones, was situated on a trade route, and satisfied a demand for trade goods. Administered trade via formal agreements and special foreign merchant laws is not a requirement. Like the port of trade, however, the gateway community was also a monopolistic market, the goods of which were used by elites to maintain their status, whereas the solar central place was but one, albeit the senior, place in a system of points in a multinodal regional exchange system. Several themes emerge from these models. Bases of trade were not common in the interior of homogenous environmental and economic zones. Peasants in large agricultural zones tended to produce all that was required for a subsistence lifestyle, and therefore had little need for trading bases. Small luxury items were obtained from itinerant merchants. Concomitant with the rise of states, tax- and rent-paying peasants were compelled to sell agricultural goods and livestock at local fairs, held periodically at a nearby center. By way of contrast, peoples living in marginal environments, such as deserts, arid grasslands, or along coasts that lacked an agricultural hinterland, pursued less diversified forms of subsistence, which necessitated that they trade with neighboring peoples in different economic environmental zones for goods that they could not produce themselves. Central Asian and Saharan desert nomads, for example, brought animal products from their flocks to entrepots/emporia or ports of trade located on the desert’s edge to trade for grain, metals, and fibers produced by local agriculturalists. In order to maximize their trade at the Savannah entrepots, such as Timbuktu, the Berber nomads of the western Sahara became intermediaries between the Maghreb and sub-Saharan Africa, transporting salt from desert oases to the savannah, where salt was scarce, returning north with gold and ivory. Like pastoral nomads, “aquatic peoples” such as the Bobangi fishermen of the middle Congo River practiced a limited form of subsistence that needed to be supplemented, trading their surplus fish at points along the river for the yams and manioc of neighboring agriculturalists. Another aquatic culture, the Greeks, whose terrain was arid, rocky, and better suited to viticulture, established emporia or ports trading colonies on the coasts of the more productive agricultural territories north of the Black Sea, where they exchanged their wine and olive oil for grain. As the more mobile and dependent trading partners, the Berbers, Bobangi, and Greeks brought their goods to agriculturalist markets, becoming middlemen as well for exchange between more distant markets. DEEP HARBORS Changes in transport technology and the emergence of rival networks influenced the location of trading bases as well. As the volume of trade increased in northeastern medieval , entrepots/emporia with shallow harbors were bypassed for deep-harbored trading settlements that could accommodate heavier cargo vessels. Advances in ship-building technology and the greater use of Mediterranean sea routes cut the cost of luxury trade with the East, causing the decline of the Champagne fairs, which depended on expensive overland routes. When ships became the dominant medium for commercial transport from the 15th to the 18th centuries, coastal sites were the main centers for interregional trade, such as Hormuz (Persian Gulf) and Gao (western India) for the Indian Ocean trade. The importance of overland bases returned in the 19th century, however, as new fairs and entrepots/emporia were established along railroad lines, such as Irkutsk and Vladivostok, which functioned as waystations for the Trans-Siberian Railroad. Attracting permanent populations from western Russia, the Trans-Siberian trading bases quickly evolved into administrative and political centers. With the modern global economy based on brokerage and credit, bases of trade are now increasingly less determined by geographic location. While port and airline facilities are still important, the presence of banking and stock market facilities, such as those in New York City, London, and Tokyo, are of prime importance for sustaining an interregional center.