Throughout the nineteenth century, Muslims in Africa expanded their activities as traders, missionaries, and warriors. In the Sudanic region, Islamic regimes were consolidated and new populations converted to Islam. From the Sudan, Muslims penetrated the Guinean forest and coastal territories of West Africa. Large numbers of people in Nigeria and Senegal were Islamized. In East Africa Gallas, Somalis, and other peoples were converted to Islam.
Between 1882 and 1900, the militant expansion of Islam was brought to a halt by European conquests. The establishment of colonial rule, however, did not stop the spread of Islam by peaceful means. In fact, colonial rule facilitated the diffusion of Islam by providing political security and expanded commercial opportunities, and by stimulating urbanization, the education of intelligentsias, and the migration of merchants and workers.
The rapid diffusion of Islam had important consequences for Islamic beliefs, communal organization, and the relation of Muslims to states and national societies. While the principal goal of many nineteenth-century Islamic movements was to establish Islamic states and a comprehensive Islamic society, colonial rule led instead to the consolidation of secular national states. Only where there are substantial Arab populations or claims to Arab identity – as in Mauritania, northern Sudan, and Somalia – is national identity expressed in Islamic terms. Only Sudan has declared itself an Islamic state. In Nigeria, Muslim identity has been integrated into the national political system, and Islamic communal organizations and concepts of justice play an important role in the internal struggle for political and social power. Elsewhere, secular elites treat their Muslim populations, however large or small, as communal constituencies. All African Muslim populations are organized as communal groups seeking state protection and patronage for their economic, educational, and foreign policy interests.