History of the Yoruba people military capital of Ilorin, and then sacked and destroyed Ọyọ-Ile, the royal seat of the Ọyọ Empire. Following this, Ọyọ-Ile was abandoned, and the Ọyọ retreated south to the present city of Oyo (formerly known as "Ago d'Oyo", or "Oyo Atiba") in a forested region where the cavalry of the Sokoto Caliphate was less effective. Further attempts by the Sokoto Caliphate to expand southwards were checked by the Yoruba who had rallied in defence under the military leadership of the ascendant Ibadan clan, which rose from the old Oyo Empire, and of the Ijebu city-states. However, the Oyo hegemony had
Oyo Empire al-Salih into his ranks. By doing this, he hoped to secure the support of Yoruba Muslims and volunteers from the Hausa-Fulani north in keeping Ilorin independent. Torn by internal struggle, Oyo could not defend itself against the Fulani. Oyo-Ile was razed by the Fulani Empire in 1835 and the Oyo Empire collapsed in 1836. To this day, the Illorin traditional ruler is an emir, whereas in the rest of Yoruba towns the rulers are called "oba" or "baale" (Baale or Baba Onile meaning "father of the land" or "lord of the land"). After the destruction of Oyo-Ile, the capital was