text: of the seventh century and continued throughout the present millennium, only came to an end, as far as territorial conquest is concerned, at the turn of this century, when European penetration brought these advances to a halt. Islam, as a religion, continued to expand, in spite of the opposition on the part of Christian missionaries. These Moslem expansions, which originally appear to have been carried on by Arabs, in later years became ethnically dissociated from them. Arabs, who everywhere in Africa intermarried freely with the native population, were frequently physically assimilated by the Africans, but attempted to preserve the religion, culture, and often the language of their Arab ancestors. Those claiming Arabian descent, however fictitious their elaim might be in reality, regarded themselves as superior to the local population, thus creating socially and ethnically stratified societies which are so typical of most of the political structures of the Sudan. The powerful emirates of Northern Nigeria, the sultanates of Bornu, Wadai, and Baghirmi in the Lake Chad region, or those of Kordofan and Dar Fur in the Anglo-Egyptian Sudan, were such strongholds of Africanized Islam. All these states are essentially conquest states in which several culturally diverse tribes of Africans were forced into one political unit by Moslem conquerors who established themselves as an aristocracy and held sway over their subject peoples.