The Oyo Empire was a West African empire of what is today southwestern Nigeria. The empire was established by the Yoruba in the 15th century and grew to become one of the largest West African states encountered by colonial explorers. It rose to preeminence through wealth gained from trade and its possession of a powerful cavalry. The Oyo Empire was the most politically important state in the region from the mid-17th to the late 18th century, holding sway not only over other Yoruba kingdoms in modern day Nigeria, Benin, and Togo, but also over other African kingdoms, most notable being the Fon Dahomey (located in modern day Benin).