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 the Alaafin of Oyo was supreme overlord of the people, he was not without checks on his power. The Oyo Mesi and the Yoruba Earth cult known as Ogboni kept the Oba's power in check. The Oyo Mesi spoke for the politicians while The Ogboni spoke for the people backed by the power of religion. The power of the Alaafin of Oyo in relation to the Oyo Mesi and Ogboni depended on his personal character and political shrewdness. The Oyo Mesi were seven principal councilors of the state. They constituted the Electoral Council and possessed legislative powers, similar to today's