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
Army of the Ethiopian Empire region. A recent convert to Judaism, he had become a client of the Sassanian Persians, avowed enemies of the Western Roman Empire. appealed for the Ethiopian Emperor. Ethiopian Imperial Army existed in one form or another since the founding of the Ethiopian Empire in the 13th century. During the First Italo–Ethiopian War, the Army of the Ethiopian Empire was able to defeat the army of the Kingdom of Italy at the battle of Adwa. During the Second Italo-Ethiopian War, the Army of the Ethiopian Empire consisted of the Imperial Bodyguard, a central army, and several armies of provincial forces. The