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 balances on the power of the Alafin and the Oyo Mesi and thus no one is arrogated absolute power. The Ogboni was a very powerful secret society composed of freemen noted for their age, wisdom and importance in religious and political affairs. Its members enjoyed immense power over the common people due to their religious station. A testament to how widespread the institution was is the fact that there were Ogboni councils at nearly all sub-courts within Yorubaland. Aside from their duties in respect to the worship of the earth, they were responsible for judging any case dealing with the