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.
Yoruba tribal marks unique to the indigenes of Oyo, Nigeria. The Abaja style of Yoruba tribal mark was inscribed on the cheeks of Lamidi Adeyemi III, the Alaafin of Oyo. The use of tribal marks as a means of identification and beautification among the Yoruba tribe is no longer a norm and some Yoruba states have enacted certain laws that prohibit the use of the marks. Violators of the law are liable to fines or imprisonment (or both). In Oyo State, for example, the prohibition of tribal marks is an integral part of the state Child Rights Law, a law that imposes a