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,
History of the Yoruba people all cases, however, Yoruba monarchs were subject to the continuing approval of their constituents as a matter of policy, and could be easily compelled to abdicate for demonstrating dictatorial tendencies or incompetence. The order to vacate the throne was usually communicated through an "aroko" or symbolic message, which usually took the form of parrots' eggs delivered in a covered calabash bowl by the senators. By the time it was the 19th century, the Kingdom had lost its control of the trade routes. The kingdom of Oyo had fallen in 1837. The Yoruba people believe there are 401 deities. The Yoruba