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 in the African slave trade during the 18th century. The Yoruba often demanded slaves as a form of tribute of subject populations, who in turn sometimes made war on other peoples to capture the required slaves. Part of the slaves sold by the Oyo Empire entered the Atlantic slave trade. Most of the city states were controlled by Obas (or royal sovereigns with various individual titles) and councils made up of Oloyes, recognised leaders of royal, noble and, often, even common descent, who joined them in ruling over the kingdoms through a series of guilds and cults. Different states saw