The Oyo Empire was a Yoruba empire in West Africa. It was located in present-day southern Benin and western Nigeria (including the South West zone and the western half of the North Central zone). The empire grew to become the largest Yoruba-speaking state through the organizational and administrative efforts of the Yoruba people, trade, as well as the military use of cavalry. The Oyo Empire was one of the most politically important states in Western Africa from the mid-17th to the late 18th century and held sway not only over most of the other kingdoms in Yorubaland, but also over nearby African states, notably the Fon Kingdom of Dahomey in the modern Republic of Benin on its west.