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
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