<P> There was a high degree of professionalism in the army of the Oyo Empire . Its military success was due in large part to its cavalry as well as the leadership and courage of Oyo officers and warriors . Because its main geographic focus was north of the forest, Oyo enjoyed easier farming and thus a steady growth in population . This contributed to Oyo's ability to consistently field a large force . There was also an entrenched military 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 . </P> <P> 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 tsetse fly . Cavalry was the long arm of the Oyo Empire . Late 16th and 17th century expeditions were composed entirely of cavalry . There were drawbacks to this . Oyo could not maintain its cavalry army in the south but could raid at will . </P> <P> Cavalry in highly developed societies such as Oyo was divided into light and heavy . Heavy cavalry on larger imported horses was armed with heavy thrusting lances or spears and also with swords . Light cavalry on smaller indigenous ponies was armed with throwing spears or bows . </P> <P> Infantry in the region around the Oyo Empire was uniform in both armor and armament . All infantry in the region carried shields, swords and lances of one type or another . Shields were four feet tall and two feet wide and made of elephant or ox hide . A 3 - foot - long (0.91 m) heavy sword was the main armament for close combat . The Yoruba and their neighbors used triple barbed javelins which could be thrown accurately from about 30 paces . </P>

Reasons for the fall of old oyo empire