Oyo Empire culture in Oyo where victory was obligatory and defeat carried the duty of committing suicide. This do-or-die policy no doubt contributed to the military aggressiveness of Oyo's generals. The Oyo Empire was the only Yoruba state to adopt cavalry; it did so because most of its territory was in the northern savannah. The origin of the cavalry is disputed; however, the Nupe, Borgu and Hausa in neighboring territories also used cavalry and may have had the same historical source. Oyo was able to purchase horses from the north and maintain them in metropolitan Oyo because of partial freedom from the
Yoruba people Africa. The historical Yoruba develop "in situ", out of earlier Mesolithic Volta-Niger populations, by the 1st millennium BCE. Oral history recorded under the Oyo Empire derives the Yoruba as an ethnic group from the population of the older kingdom of Ile-Ife. The Yoruba were the dominant cultural force in southern Nigeria as far back as the 11th century. The Yoruba are among the most urbanized people in Africa. For centuries before the arrival of the British colonial administration most Yoruba already lived in well structured urban centres organized around powerful city-states ("Ìlú") centred around the residence of the "Oba". In