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
Yoruba people There are three major dialect areas: Northwest, Central, and Southeast. As the North-West Yoruba dialects show more linguistic innovation, combined with the fact that Southeast and Central Yoruba areas generally have older settlements, suggests a later date of immigration for Northwest Yoruba. The area where North-West Yoruba (NWY) is spoken corresponds to the historical Oyo Empire. South-East Yoruba (SEY) was probably associated with the expansion of the Benin Empire after c. 1450. Central Yoruba forms a transitional area in that the lexicon has much in common with NWY, whereas it shares many ethnographical features with SEY. Literary Yoruba, the standard