Kosoko was the Oba of Lagos between 1845 and 1851. His insistence on slave trade was the pretext for the 1851 British bombardment of Lagos for which he went into exile in Epe, a town 60 kilometers from Lagos. Kosoko himself had ousted his uncle, Akitoye from the throne to become king but the less dynamic Akitoye had been able to regain his seat through the support of the British who for the purpose of business and Christian pressure decided to support the deposed king and his Badagry allies against Kosoko. Oba Kosoko’s conviction about slavery was firm and superstitious, so he refused to sign the anti-slavery treaty of the British. He continued in the now illegal trade even during his exile, but he was not an easy man to put aside. He involved himself in the politics of his refuge place, and had to be consulted during the negotiations for the cession of Lekki to the British crown.
Kosoko was a tall, muscular man whose intelligence was hailed as been superior to the people around him and comparable to the well-practiced Europeans he came in contact with. His efforts to regain the Lagos seat was futile but the colonial governor of Lagos, John Hawley Glover allowed him and his court to return from exile in 1863. Kosoko died in 1872. His sword and other paraphernalia are being preserved at Iga Ereko in Lagos. Oba Oyekan I many years later promoted his descendant, Asajon Oloja as a chief.