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 been dealt a mortal blow. The other Yoruba city-states broke free of Oyo dominance, and subsequently became embroiled in a series of internecine conflicts that soon metamorphosed into a full scale civil war. These events weakened the southern Yorubas in their resistance to British colonial and military invasions. In 1960, greater Yorubaland was subsumed into the Federal Republic of Nigeria. The historical records of the Yoruba, which became more accessible in the nineteenth century with the more permanent arrival of the Europeans, tell of heavy Jihad raids by the mounted Fulani warriors of the north as well as of endemic