At the battle of Ilorin in 1835, Alaafin Oluewu fought in the centre of the army with his ally, Eleduwe , king of Nikki ( now in Benin Republic ). However, the Yoruba chiefs , with the exception of those of Ibadan, deserted the king and the day was lost .
As a result , the Fulani captured Oluewu and put him to death. They sacked Oyo -Ile which led to the abandonment of Old Oyo by the Yoruba.
When Atiba Atobatele succeeded Oluewu as Alaafin in 1838, he refounded Oyo and moved the capital to Ago Oja ( present Oyo). The Ibadan chiefs then decided that the Alaafin should no longer go to war, no matter what . It has remained so till this day.