THE ORDER OF YORUBA KINGS’ RANKING

There has been a lot of controversy in the ranking made by the Alake of Abeokuta, when the Oonirisa visited the place. Salary received by kings cannot be used as a criterion to determine the rank of an Oba. My criteria is to look at the actual area captured by the Oba and to see the extent of his empire, the depth of his civilization , and how many people were loyal to the king of the kingdom. 

Following the criteria listed above, The Oonirisa will be the greatest of all the Yoruba kings. 

The reasons will be as follows
a. It is the oldest kingdom, every other Yoruba kingdom emanated from it

b. It was more civilized than any other kingdom. Herodotus , the father of History , listed Ife as the five important cities in Africa.
c. Ife is the shrine of the Yoruba nation. All the major shrines of Yorubaland - Ogun, Obatala, Orunmila, Olokun, and a host of others have their headquarters in Ife.
d. Cloth weaving, bronze making, etc begn from Ife ; or, became perfected in Ife
e. The Ifa Oracle system began in Ife. With its mathematical precision, using binary system, and a plethora of poems, it is the greatest oracle to be invented by mankind
f. All Yoruba kings received their crowns from Ife

Next to Ife will be Benin or Oyo. 

Benin captured most of the forest belts, and some coastal stretch of land . Oyo captured and conquered all Yoruba and non-Yoruba states in the Savanna Belt. But Benin will be taken as greater than Oyo . 

Reasons
Benin was only once defeated, when they confronted the Isekiri in 1786(Captain Landolphe 1790). After the establishment of the fort at Ugborodo (Borodo ) in the French document, the Oba Ehengbuda(Ifediora2006) decided to attack Warri. The Bini conscripted their Lagos (Awori , but Aunis in the French document) subjects and got the aid of the British who were jealous of the French fort. But too bad, the Isekiri king , Erejuwa , was strong. Getting some support from France he – together with his general s Iyatsere Okorodudu and Ologbotsere Eyinmisan - -defeated the Binis and their allies, the British and the Aworis. The chiefs of Lagos were sold as slaves in Calabar. 

Apart from this singular defeat, the Binis did not suffer any further defeat. But the Oyos suffered so many defeats in history, some from Nupe,, Fulani etc(Akinjogbin 1977),. Oyo was as a result defeated by in Nupe in 1791 because of the growth in trade of firearms. Oyo had no strong army during the century when she had to face the greater military challenges in her history. Also the slaves and horses to the cavalry was blocked. Another contributory factor to the collapse of Oyo Empire was the constitutional crises and the civil wars which started from Aole's reign.(Akin Fasanya ) online.

So, I will take Benin to be the second greatest Yoruba Empire. Oyo is third.
After Ife, Oyo and Benin, the next Yoruba empires will be Ijebu, Warri, Owo. Warri comes next because she was in active control of most of the Niger delta sub region; it was the most reknowned kingdom in the whole of the Niger delta and her influences was felt as far as Cameroun (Olomu 2015). Its religion spread all through the Delta of the Niger (Alagoa1989). The Urhobos, Ijaws of Delta – Burutu, Ogulagha, Odimodi, Mein etc were under her dominion (Moore1936).
Ijebu was also a power to be reckoned with. They were mentioned in most European documents as a powerful kingdom before the 16th century . owo is also a powerful state. Then in the 19th century, Ibadan rose as a power.
So, by the extent of empire, the following will be the most important Yoruba kingdoms:
1. Ife
2. Benin
3. Oyo
4. Warri (Isekiri)
5. Ijebu
6. Owo
7. Ibadan

NB , for the great importance of Benin, Warri and Ijebu as mega kingdoms see Joseph Kenny online – “THE CATHOLIC CHURCH
IN TROPICAL AFRICA

1445-1850

by
Joseph Kenny, O.P.
Counting Egba as an important kingdom is asking for too much. Egba at a time was under Ijebu.
Augustine Oritseweyinmi Oghanrandukun Olomu (St.Ifa)