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
West Africa all-powerful Akan Empire of Ashanti, while Ife rose to prominence around the 14th century. Further east, Oyo arose as the dominant Yoruba state and the Aro Confederacy as a dominant Igbo state in modern-day Nigeria. The Kingdom of Nri was a West African medieval state in the present-day southeastern Nigeria and a subgroup of the Igbo people. The Kingdom of Nri was unusual in the history of world government in that its leader exercised no military power over his subjects. The kingdom existed as a sphere of religious and political influence over a third of Igboland and was administered by