Oyo Empire metropolitan Oyo. This may have been fine in the 15th century when Oyo controlled only its heartland. But to make and maintain farther conquest, the structure underwent several changes. Oyo maintained a semi-standing army of specialist cavalry soldiers called the "Eso", the "Esho" or, formally, the Eso of Ikoyi. These were 70 junior war chiefs who were nominated by the Oyo Mesi and confirmed by the Alaafin of Oyo. The Eso were appointed for their military skill without regard to heritage and were led by the Are-Ona-Kakanfo. After Oyo's return from exile, the post of Are-Ona-Kakanfo was established as the
Yoruba people others. These varieties, or spiritual lineages as they are called, are practiced throughout areas of Nigeria, the Republic of Benin, Togo, Brazil, Cuba, Guyana, Haiti, Jamaica, Puerto Rico, Suriname, Trinidad and Tobago, the United States, Uruguay, Argentina and Venezuela, among others. As interest in African indigenous religions grows, Orisha communities and lineages can be found in parts of Europe and Asia as well. While estimates may vary, some scholars believe that there could be more than 100 million adherents of this spiritual tradition worldwide. Oral history of the Oyo-Yoruba recounts Odùduwà to be the Progenitor of the Yoruba and the