The Almoravids
The Almoravids were originally Muslims from Morocco who settled in the area immediately north of the Ghana Kingdom around 1050. Under the leadership of Abu Bakr, the Almoravids unified their fellow Muslims and gained important allies from among the local non-Muslim people. Abu-Bakr then led his followers against the kingdom of Ghana in 1054. The Soninke managed to resist the Almoravids until 1076, when Abu-Bakr and his followers finally conquered the capital of Ghana. The Almoravids, however, could not maintain unity in Ghana, and Abu-Bakr died in 1087 while suppressing a rebellion.
Source: Davidson, Basil. A History of West Africa. Longman, 1981.