Oyo Empire metropolitan Oyo. This may have been fine in the 15th century when Oyo controlled only its heartland. But to make and maintain farther conquest, the structure underwent several changes. Oyo maintained a semi-standing army of specialist cavalry soldiers called the "Eso", the "Esho" or, formally, the Eso of Ikoyi. These were 70 junior war chiefs who were nominated by the Oyo Mesi and confirmed by the Alaafin of Oyo. The Eso were appointed for their military skill without regard to heritage and were led by the Are-Ona-Kakanfo. After Oyo's return from exile, the post of Are-Ona-Kakanfo was established as the
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