West Africa a priest-king called as an Eze Nri. The Eze Nri managed trade and diplomacy on behalf of the Nri people and possessed divine authority in religious matters. The Oyo Empire was a Yoruba empire of what is today Western and North central Nigeria. Established in the 15th century, the Oyo Empire grew to become one of the largest West African states. It rose through the outstanding organizational skills of the Yoruba, wealth gained from trade and its powerful cavalry. The Oyo Empire was the most politically important state in the region from the mid-17th to the late 18th century, holding
Yoruba people the monarchy was open to the election of any free-born male citizen. In Ilesa, Ondo, Akure and other Yoruba communities, there were several, but comparatively rare, traditions of female "Ọbas". The kings were traditionally almost always polygamous and often married royal family members from other domains, thereby creating useful alliances with other rulers. Ibadan, a city-state and proto-empire founded in the 18th century by a polyglot group of refugees, soldiers, and itinerant traders from Ọyọ and the other Yoruba sub-groups largely dispensed with the concept of monarchism, preferring to elect both military and civil councils from a pool of eminent