Oyo Empire 17th century, Oyo began a long stretch of growth, becoming a major empire. Oyo never encompassed all Yoruba-speaking people, but it was the most populous kingdom in Yoruba history. The key to Yoruba rebuilding of Oyo was a stronger military and a more centralized government. Taking a cue from their Nupe enemies (whom they called "Tapa"), the Yoruba rearmed with armor and cavalry. Oba Ofinran, Alaafin of Oyo, succeeded in regaining Oyo's original territory from the Nupe. A new capital, Oyo-Igboho, was constructed, and the original became known as Old Oyo. The next oba, Eguguojo, conquered nearly all of Yorubaland.
Oyo Empire 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 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. The Oyo Empire, like many empires before it, used both local and tributary forces to expand its domains. The structure of the Oyo military prior to its imperial period was simple and closer aligned to the central government in