History of the Yoruba people military capital of Ilorin, and then sacked and destroyed Ọyọ-Ile, the royal seat of the Ọyọ Empire. Following this, Ọyọ-Ile was abandoned, and the Ọyọ retreated south to the present city of Oyo (formerly known as "Ago d'Oyo", or "Oyo Atiba") in a forested region where the cavalry of the Sokoto Caliphate was less effective. Further attempts by the Sokoto Caliphate to expand southwards were checked by the Yoruba who had rallied in defence under the military leadership of the ascendant Ibadan clan, which rose from the old Oyo Empire, and of the Ijebu city-states. However, the Oyo hegemony had
Oyo Empire despite its violent creation, it was held together by mutual self-interest. The government was able to provide unity for a vast area through a combination of local autonomy and imperial authority. Unlike the great savannah empires, of which Oyo may not be called a successor since it was a successor of Ife, there was little if any Muslim influence in the empire. It is known that at least some Muslim officials were kept in Metropolitan Oyo, and men capable of writing and calculating in Arabic were reported by French traders in 1787. Many believe the decline of the Oyo empire