2. Bini empire which was on a crisis being at that time seemed it have for Oraamiyan to rule, this made him to fled Bini empire and instead if going back to Ile-Ife, went straight to establish the Oyo empire at a land, 150 miles north of Ile-Ife.
3. The Oba was the Alafin of Oyo, the occupant of the throne and owner of the palace. The Alaafin was only seen three times in a year, during the Ifa, Ori and Bere festivals. He holds office for life. He was seen as the representative of the God.
4. The Alaafin was assisted in the administration of the empire by a group of seven chiefs, known as the Oyomesi. The Oyomesi was the supreme council and acted as watchdogs to the Alaafin. They were kingmakers and thus ensured that the Alaafin did not wield arbitrary powers.
5. The Beshorun was the head of the Oyomesi. If the Alaafin became tyrannical or unpopular. The Beshorun will present a calabash to the Alaafin, which meant that he had been rejected by his people, consequent upon which he will commit suicide.
6. The Eso and the Ilari also assisted the Alaafin. The Eso were the military elites stationed at the outskirt of the city.
7. The Aare Ona Kakanfo was their head and was a must for the Aare Ona Kakanfo was their head and the supreme commander of the army. In war times, victory was a must for the Aare Ona Kakanfo, while a defeat led to his committing suicide.
8. The Ilari acted as representatives of the king. They also collected tributes for the Alaafin.
9. The Ogboni Cult and talented men, who served as a check on the excessive powers of Alaafin and the Oyomesi thereby making the empire democratic as they provided proper checks and balances in the various arms of government in the empire.
10.The ultimate collapse of Oyo empire could be attributed to the invasion of the Fulani Jihadists. The fact was that Afonja, an ambitious Aare Ona Kakanfo, had invited the Jihadist to help him conquer the Ilorin area of the empire for himself. However, his invitees later turned against him and killed him. They made Ilorin part of the Sokoto caliphate, from where they made advances southwards and in 1937, captured the entire Oyo empire (Ibid). this development marked the collapse of the Oyo empire.
Special credit goes to the book History of Nigeria by Falola T, M etal as a point of reference.