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,
Yoruba people ancient times, most of these cities were fortresses, with high walls and gates. Yoruba cities have always been among the most populous in Africa. Archaeological findings indicate that Òyó-Ilé or Katunga, capital of the Yoruba empire of Oyo (fl. between the 11th and 19th centuries CE), had a population of over 100,000 people (the largest single population of any African settlement at that time in history). For a long time also, Ibadan, one of the major Yoruba cities, was the largest city in the whole of Sub Saharan Africa. Today, Lagos (), another major Yoruba city, with a population of