Just discovered Ousmane Sembène, one of the founders of (black) African cinema. One of his movies, Ceddo (1977) presents the relatively undiscovered historical topic of the Islamization of black Africa, the conflict of Islam and Christianity intertwined with ethnic relations, traditional values, and the slave trade. It was banned in Senegal.

You can read more about the movie on Wikipedia, IMDB and Senses of Cinema.