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,
Yoruba people There are three major dialect areas: Northwest, Central, and Southeast. As the North-West Yoruba dialects show more linguistic innovation, combined with the fact that Southeast and Central Yoruba areas generally have older settlements, suggests a later date of immigration for Northwest Yoruba. The area where North-West Yoruba (NWY) is spoken corresponds to the historical Oyo Empire. South-East Yoruba (SEY) was probably associated with the expansion of the Benin Empire after c. 1450. Central Yoruba forms a transitional area in that the lexicon has much in common with NWY, whereas it shares many ethnographical features with SEY. Literary Yoruba, the standard