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 first oba (king) of Oyo, was succeeded by Oba Ajaka, Alaafin of Oyo. Ajaka was deposed, because he lacked Yoruba military virtue and allowed his sub-chiefs too much independence. Leadership was then conferred upon Ajaka's brother, Shango, who was later defined as the deity of thunder and lightning. Ajaka was restored after Sango's death. Ajaka returned to the throne thoroughly more warlike and oppressive. His successor, Kori, managed to conquer the rest of what later historians would refer to as metropolitan Oyo. The heart of metropolitan Oyo was its capital at Oyo-Ile (also known as "Oyo Katunga" or "Old Oyo"