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
Yoruba people in the African slave trade during the 18th century. The Yoruba often demanded slaves as a form of tribute of subject populations, who in turn sometimes made war on other peoples to capture the required slaves. Part of the slaves sold by the Oyo Empire entered the Atlantic slave trade. Most of the city states were controlled by Obas (or royal sovereigns with various individual titles) and councils made up of Oloyes, recognised leaders of royal, noble and, often, even common descent, who joined them in ruling over the kingdoms through a series of guilds and cults. Different states saw