Origins. As Adu Boahen has explained, the trans- Saharan caravan trade began to take place on a regular basis during the fourth century, as an expanded version of the pre-existing intra- and interregional trade among peoples of the forest, savanna, Sahel, and Sahara. While Ghana was an integral part of the early trans-Saharan trade, neither it nor any other Western Sudan state was built by, or specifically for, the trans-Saharan trade. Fundamentally important to the success of the Empire of Ghana between the eighth and twelfth centuries, this trading system reached its peak during the fourteenth through sixteenth centuries, during the heydays of the Mali and Songhai Empires.

Routes. There were seven primary north-south routes, six principal forest routes, and two west-east routes. During the 500-1590 period, routes rose and declined in importance depending on the empire in...