Why Oba of Lagos 'snubbing' Ooni of Ife shocked Nigeria

Yoruba leader, known as the Ooni of Ife.

Deep respect for leaders is a pillar of the culture of the Yoruba people, one of Nigeria's biggest ethnic groups.
But at a recent public event a Yoruba leader, known as the Oba of Lagos, Rilwan Akiolu ,74, refused to properly greet the Ooni of Ife, Adeyeye Ogunwusi 42.
As the Ooni leaned over to greet the Oba by shaking his hand, what he got instead was a dismissive wave and what looked like a scowl of disdain.
It's quite unheard of for traditional leaders to rebuff each other in public. And for a lesser leader, like the Oba, to rebuff the Ooni of Ife, the spiritual head of all Yoruba people, is an even graver offence.
Though there are various interpretations by historians and scholars on the origins of Yoruba people, the Ooni of Ife is widely acknowledged as the overall leader and is known as the "king of kings".
The Oba - of which there are up to 50 in Lagos alone - is seen to be a lesser traditional ruler, even though he is older.
It is not clear yet what upset the Oba of Lagos. But there is speculation it could relate to a spat that goes back over a century.
A long rivalry existed between the two thrones even before the colonial era.
The ancestors of the Oba of Lagos were loyal to the powerful Benin kingdom, an area south-east of Lagos rather than the Ooni to the north-east.
But on independence, the country was divided into different political zones. Lagos fell into roughly the same zone as the Ooni of Ife.