Imagbon War was the designation given to the military intervention of the British colonial authority in Ijebu that led to the lost of independence of the kingdom. The final battle by which Ijebu fell took place on 19 May 1892 at the village of Imagbon. This short war that claimed the lives of up to a thousand Ijebu led to the annexation of their land with the Southern protectorate of Nigeria before the terminal amalgamation of the whole country in 1914. In the war, the British army which included African mercenaries, 1,200 strong, was led by a Scott who had fought in the Ashanti war of 1874. The Ijebu army consisted of obdurate young men who were totally unaware of even the possibility of reaching any last minute agreement that will prevent confrontation with their adversary. In the war, the British appeared at Epe, against the expectation of the Ijebu who hoped to corner them at Itoikin, where their emissaries always took. This was about the first time guns will be used in a major West African expedition. With their battalion lined along the Yemoji River, two miles long, the Ijebu warriors were easily felled.
Although it was apparent since the British take-over of the neighboring coastal Lagos town in 1861 that the interior will follow, the Ijebu, just few miles away from the new colony, still persisted in their parochial manner. The king, Aboki Tunwase’s invitation of the British to intervene in ending the Kiriji War that was taking its toll on Ijebu provided an all-too-easy beginning for the end of his kingdom’s much cherished independence. Incursion of Lagos Special Commissioners provided a hiatus that was seized by foreign travelers who now favored the Ijebu route over their former Ondo route. Some of these intruding travelers were treated with hostility- an act that would incense the British Civil servant, Thomas Carter who, having heard of the Anglo-Ijebu relations which seemed to favor the latter, resumed his new appointment in Lagos with a predetermined mind. His attempt to resuscitate a 1852 treaty in which Ijebu territory was opened up for travels and toll collection banned met with passive resistance, but signatures were in the end, secured. Ijebu blatant disregard for this treaty, and their proclaimed disavowal formed the needed causa belli for the military action of 1892.
On 12 May, soldiers composed of Hausa and troops from the Gold Coast, numbering less than 500 left Lagos and in the following week the Ijebu were defeated after an unexpected stiff resistance. Aftermath of the 1892 military expedition was marked by general change in attitude, as leaders now considered colonial policies more kindly, having seen the muscle of colonial will. Opportunity was provided for the Christian Missionary Society which swept through the land with a zeal that is unique in the whole of Nigeria.