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
Oyo Empire The Oyo did not use guns in its major conquests. The military waited until the 19th century to adopt them. In 1764, a joint Akan (Akyem)-Dahomey-Oyo force defeated an Asante army. The alliance victory defined borders between the neighboring states. Oyo led a successful campaign into Mahi territory north of Dahomey in the late 18th century. The Yoruba also used the forces of their tributaries; for instance, they accomplished a 1784 naval blockade of Badagri with an Oyo-Dahomey-Lagos force. At the beginning, the people were concentrated in metropolitan Oyo. With imperial expansion, Oyo reorganized to better manage its vast holdings