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 and armament. All infantry in the region carried shields, swords and lances of one type or another. Shields were four feet tall and two feet wide and made of elephant or ox hide. A heavy sword was the main armament for close combat. The Yoruba and their neighbors used triple barbed javelins which could be thrown accurately from about 30 paces. The Oyo Empire, like many empires before it, used both local and tributary forces to expand its domains. The structure of the Oyo military prior to its imperial period was simple and closer aligned to the central government in