Oyo Empire could act as a buffer between Oyo and Imperial Benin. By the end of the 16th century, the Ewe and Aja states of modern Benin were paying tribute to Oyo. The reinvigorated Oyo Empire began raiding southward as early as 1682. By the end of its military expansion, Oyo's borders would reach to the coast some southwest of its capital. It met little serious opposition until the early 18th century. In 1728, the Oyo Empire invaded the Kingdom of Dahomey in a major campaign of its cavalry. Dahomey warriors, on the other hand, had no cavalry but many firearms. Their
Oyo Empire first oba (king) of Oyo, was succeeded by Oba Ajaka, Alaafin of Oyo. Ajaka was deposed, because he lacked Yoruba military virtue and allowed his sub-chiefs too much independence. Leadership was then conferred upon Ajaka's brother, Shango, who was later defined as the deity of thunder and lightning. Ajaka was restored after Sango's death. Ajaka returned to the throne thoroughly more warlike and oppressive. His successor, Kori, managed to conquer the rest of what later historians would refer to as metropolitan Oyo. The heart of metropolitan Oyo was its capital at Oyo-Ile (also known as "Oyo Katunga" or "Old Oyo"