The area known as the western Sudan encompasses the broad expanse of savanna that stretches between the vast Sahara Desert to the north and the tropical rain forests of the Guinea coast to the south. Its name comes from bilad-al-sudan, or "Land of Blacks," the term used by the Arabic travelers, geographers, and historians who first wrote of the region's history. In spite of tantalizing archaeological remains, our understanding of the great medieval kingdoms of the western Sudan remains dependent upon and limited by these early written sources. The period prior to Islamic contact is still largely unknown.
The medieval empires of Ghana, Mali, and Songhai that controlled the western Sudan had no fixed geopolitical boundaries or singular ethnic or national identities. Although each empire possessed important political and economic centers, such as Ghana's Kumbi Saleh and Songhai's Gao, it is not certain that these were permanent capitals. Instead, the empires may have had "floating" capitals that shifted between a number of urbanized centers or traveled with their ruling monarchs. Above all, the empires of the western Sudan were unified by strong leadership, kin-based societies, and the trade routes they sought to dominate.
The importance that contact with the Islamic world held for these empires cannot be understated. While extensive trading networks undoubtedly predated Arabic involvement, the development of trans-Saharan commerce in the seventh century by Arabs and Berbers intensified and expanded the trading networks that made the empires of the western Sudan possible. The savanna region is naturally hospitable to both agriculture and livestock breeding and is ideally situated for trade. An easily traversed region separating radically different environments, each possessing resources and products badly needed by the other, it is likely that the savanna was an important trading arena long before the first camel caravans arrived from northern Africa (third to fourth century A.D.).
Although a rich diversity of goods were exchanged, all the empires of the western Sudan were primarily based upon control of the lucrative trans-Saharan trade in gold and salt. Gold, mined predominantly in southern West Africa, was much sought after by both African rulers and traders bound for northern Africa and Europe. Salt was essential in the regions south of the Sahara both as a dietary supplement and a preservative. Strategically located between southern gold-producing regions and Saharan salt mines like Taghaza, the kingdoms of the western Sudan were well positioned to amass great wealth through the taxation of imports and exports.
Securing vast trading territories required mobility, and if the camel facilitated trans-Saharan trade, it was the horse that enabled empires to dominate it. Horses were so highly prized that only the wealthy and powerful could own them, and the impressive cavalries of such rulers as the Soso king Sumanguru Kante and the Songhai emperor Sonni cAli Ber are well remembered in written and oral histories. In sculptural arts, the importance of horses came to be reflected in numerous depictions of stately figures on horseback. Equestrian figures carved of wood or cast in metal became important emblems of power and were produced for centuries throughout the western Sudan.
For more information concerning the complex history of Islam and Africa, see Trade and the Spread of Islam.