History of Nigeria city-states. A state council (the "Oyo Mesi") named the "Alaafin" (king) and acted as a check on his authority. Their capital city was situated about 100 km north of present-day Oyo. Unlike the forest-bound Yoruba kingdoms, Oyo was in the savanna and drew its military strength from its cavalry forces, which established hegemony over the adjacent Nupe and the Borgu kingdoms and thereby developed trade routes farther to the north. The Benin Empire (1440–1897; called "Bini" by locals) was a pre-colonial African state in what is now modern Nigeria. It should not be confused with the modern-day country called Benin,
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