Yoruba state in present-day southwestern Nigeria that dominated the land between the Volta and Niger rivers in 1650–1750.
Two waves of immigrants probably entered the area с AD 700–1000, and the second wave formed a state at Oyo. This state became preeminent among Yoruba states because of its good trading position, natural resources, and industrious inhabitants. Though at first less powerful than its neighbours, by the end of the 16th century its ruler, Orompoto, had used trade-derived wealth to maintain a trained army. In the 18th century Oyo subjugated the Dahomey kingdom and had begun trading with European merchants at Dahomey's ports. Oyo's wealth increased, but Abiodun (r. с 1770–90) neglected the army and the possibilities for territorial expansion, thus weakening central authority for his successor. Soon after 1800 Oyo was captured by Fulani Muslims from Hausaland. See also Hausa .