The Oyo Empire was a Yoruba empire in West Africa. It was located in present-day eastern 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.
History
Legend of origin
The origins of the Oyo Empire lie with Oranyan (also known as Oranmiyan), the last prince of the Yoruba Kingdom of Ile-Ife (Ife). Oranmiyan made an agreement with his brother to launch a punitive raid on their northern neighbors for insulting their father Oduduwa, the first Ooni of Ife. On the way to the battle, the brothers quarreled and the army split up. Oranmiyan's force was too small to make a successful attack, so he wandered the southern shore of the Niger River until reaching Bussa. There, the local chief entertained him and provided a large snake with a magic charm attached to its throat.

The chief instructed Oranmiyan to follow the snake until it stopped somewhere for seven days and disappeared into the ground. Oranmiyan followed the advice and founded Oyo where the serpent stopped. The site is remembered as Ajaka. Oranmiyan made Oyo his new kingdom and became the first "oba" (meaning 'king' or 'ruler' in the Yoruba language) with the title of "Alaafin of Oyo" (Alaafin means 'owner of the palace' in Yoruba). He left all his treasures in Ife and allowed another king to rule there.

At one time, Oyo-Ile was at war with the Bariba of Borgu, who wanted to subjugate the new city then still under construction. Orangun Ajagunla of Ila, Oranmiyan's elder brother, stormed in with his men to assist. Not long after the war was won, Oranmiyan had a son, Ajuwon Ajaka, by Princess Torosi of the Tapa (Nupe); much later Arabambi was also born by the same woman. It is believed that the name "Sango" was given by his maternal grandfather or that he adopted it from the local name for the god of Thunder. Either way, the royal family was devoted to the Spirits of Thunder (Jakuta) and War (Ogun).

Early period (13th century–1535) The founding of Oyo is regarded as 1300, but this is only estimated through backtracking the chronology.
Oranmiyan, the first oba (king) of Oyo, was succeeded by Oba Ajaka, Alaafin of Oyo. Ajaka was deposed, because he lacked Yoruba military virtues and allowed his sub-chiefs too much independence. Leadership was then conferred upon Ajaka's brother, Shango, who was later deified as the deity of thunder and lightning. Ajaka was restored after Sango's death. Ajaka returned to the throne thoroughly more warlike. His successor, Kori, managed to conquer the rest of what later historians would refer to as metropolitan Oyo.
Oyo Ile
The heart of metropolitan Oyo was its capital at Oyo-Ile (also known as Oyo Katunga, Old Oyo or Oyo-Oro). The two most important structures in Oyo-Ile were the 'Afin,' or palace of the Oba, and his market. The palace was at the center of the city close to the Oba's market called 'Oja-Oba'. Around the capital was an enormous earthen wall for defense with 17 gates. The importance of the two large structures (the palace and the Oja Oba) signified the importance of the king in Oyo.
The Nupe occupation
Oyo had grown into a formidable inland power by the end of the 14th century. For over a century, the Yoruba state had expanded at the expense of its neighbors. During the reign of Onigbogi, Oyo suffered military defeats at the hands of the Nupe led by Tsoede. Sometime around 1535, the Nupe occupied Oyo and forced its ruling dynasty to take refuge in the kingdom of Borgu. The Nupe sacked the capital, destroying Oyo as a regional power until the early 17th century.
Imperial period (1608–1800)
The Yoruba of Oyo went through an interregnum of 80 years as an exiled dynasty after its defeat by the Nupe. They re-established Oyo to be more centralized and expansive than ever. The people created a government that established its power over a vast territory. During the 17th century, Oyo began a long stretch of growth, becoming a major empire. Oyo never encompassed all Yoruba people, but it was the most populous kingdom in Yoruba history.





