Islam was still a new faith when it was carried across North Africa and down the East African coast. Within six hundred years of the Prophet's death it had penetrated the Sahara to the Sudanic belt stretching from the Atlantic to the Red Sea. By the late nineteenth century the range of Islamic institutions in Africa's Muslim communities resembled the complexity of those in the heartlands of Islam; indeed, the northern third of Africa was firmly integrated into the Islamic world, both through the faith itself and through its overlapping economic networks. The region that was to provide a testing ground for Islam during our period was the middle third of the continent. There the combined forces of Christian missions and colonial governments generally sought to mitigate or at least control the advance of Islam, and Muslim communities were thereby spurred on to answer this challenge, occasionally under the aegis of the Europeans but also in contradiction to the Western values associated with the colonial order.

The particular adaptations of Islam in sub-Saharan Africa were typical of the variety of Muslim communities on other frontiers of the Islamic world. There were a few Shi‘ite communities in North Africa and along the East African coast, but nearly all African Muslims were ‘orthodox’ Sunnī. Islamic law (sharī‘a) and the scholars (‘ulamā‘) and jurists (qadis) who interpreted it served as the foundation for each community, whether a cluster of nomads’ tents or a polity of several million souls. Among the four schools of Islamic law, two were widely represented in Africa: the Māliki rite predominated in North Africa and West Africa, and the Shāfi‘i school in East Africa.