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 orders from Oyo were strictly followed, and access to local markets was provided to Oyo merchants. The Oyo often demanded tribute in slaves. The tributary sometimes made war on other peoples to capture slaves for this. Oyo punished disobedience by wholesale slaughter of the community, as it accomplished in Allada in 1698. The Oyo Empire developed a highly sophisticated political structure to govern its territorial domains. Scholars have not determined how much of this structure existed prior to the Nupe invasion. Some of Oyo's institutions are clearly derivative of early accomplishments in Ife. After reemerging from exile in the early