History of Africa usually governed by an "oba" and an "iwarefa", a council of chiefs who advised the "oba." by the 18th century, the Yoruba city-states formed a loose confederation, with the "Oni" of Ife as the head and Ife as the capital. As time went on, the individual city-states became more powerful with their "obas" assuming more powerful spiritual positions and diluting the authority of the "Oni" of Ife. Rivalry became intense among the city-states. The Oyo Empire rose in the 16th century. The Oyo state had been conquered in 1550 by the kingdom of Nupe, which was in possession of cavalry,
Yoruba people in the Atlantic slave trade Yoruba people in the Atlantic slave trade The Yoruba people, among the most heavily targeted, contributed significant cultural and economic influence upon the Atlantic slave trade during its run from approximately 1400 until 1900 CE. From 1400 onward, the Oyo Empire's imperial success made the Yoruba language a "lingua franca" almost to the shores of the Volta. Toward the end of the 18th century, the Oyo army was neglected as there was less need to conquer. Instead, Oyo directed more effort towards trading and acted as middlemen for both the Trans-Saharan and Trans-Atlantic slave trade. Europeans bringing salt arrived in