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 little other than the displays of royal wealth. Most of the city states were controlled by "Obas", elected priestly monarchs, and councils made up of "Oloyes", recognised leaders of royal, noble, and often even common descent, who joined them in ruling over the kingdoms through a series of guilds and cults. Different states saw differing ratios of power between the kingship and the chiefs' council. Some, such as Oyo, had powerful, autocratic monarchs with almost total control, while in others such as the Ijebu city-states, the senatorial councils were supreme and the Ọba served as something of a figurehead. In