Oyo Empire gunshots scared the Oyo cavalry horses and prevented their charging. Dahomey's army also built fortifications such as trenches, which forced the Oyo army to fight as infantry. The battle lasted four days, but the Yoruba were eventually victorious after reinforcements arrived. Dahomey was forced to pay tribute to Oyo. The Yoruba invaded Dahomey seven times before finally subjugating the small kingdom in 1748. With its cavalry, Oyo campaigned successfully in conquest and suppression over great distances. The Oyo army was able to attack defensive fortifications, but it was harder to supply an army, and they withdrew when supplies ran out.
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