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
Oyo Empire preventing the Alaafin from being an autocrat; the Oyo Mesi compelled many Afaafin to commit suicide during the 17th and 18th centuries. The head of the council of Oyo Mesi, the Bashorun, consulted the Ifa oracle for approval from the gods. New alaafins of Oyo were seen as appointed by the gods. They were regarded as "Ekeji Orisa," meaning "companion of the gods." The Bashorun had final say on the nomination of the new Alaafin, his power rivaling the king himself. For example, the Bashorun orchestrated many religious festivals; in addition to being commander-in-chief of the army, which gave him