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,
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