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 variety taught in schools and spoken by newsreaders on the radio, has its origin in the Yoruba grammar compiled in the 1850s by Bishop Samuel Ajayi Crowther, who himself was a creole from Sierra Leone. Though for a large part based on the Oyo and Ibadan dialects, it incorporates several features from other dialects. As of the 7th century BCE the African peoples who lived in Yorubaland were not initially known as the Yoruba, although they shared a common ethnicity and language group. By the 8th century, a powerful Yoruba kingdom already existed in Ile-Ife, one of the earliest in