Anglo - Aro War The Anglo – Aro War ( 1901 – 1902 ) was a conflict between the Aro Confederacy in present day Eastern Nigeria , and the British Empire . The war began after increasing tension between Aro leaders and British colonialists after years of failed negotiations . Cause of the war . The Aro Confederacy , whose powers extended across Eastern Nigeria and beyond was challenged in the last decades of the 19th century by increasing British penetration of the hinterland . The Aro people and their allies resisted the penetration which threatened their culture , influence , and sovereignty . Reasons for the war advanced by Sir Ralph Moore , the British High Commissioner of the Nigerian Coast Protectorate , included : Aro Opposition . The Aros knew that British penetration would destroy their economic dominance of the hinterland . They also opposed their religion , Christianity , which threatened their religious influence through their oracle Ibini Ukpabi . The Aro led raids and invasions on communities were conducted in order to undermine British penetration since the 1890s . While the British prepared for the invasion of Arochukwu in November 1901 , the Aro launched their last major offensive before the Aro Expedition by British forces . Aro forces led by Okoro Toti sacked Obegu ( a British ally ) which resulted in 400 people dying . This attack quickened British preparation for their offensive . Aro Expedition . Sir Ralph Moore and the Royal Niger Company , had planned the attack on the Aros and the Ibini Ukpabi oracle since September 1899 but due to lack of necessary manpower , was delayed until November 1901 . On November 28 , Lt . Col . A . F . Montanaro led 87 officers , 1 , 550 soldiers and 2 , 100 carriers in four axes of advance to Arochukwu from Oguta , Akwete , Unwuna and Itu on a counter - insurgency campaign . As expected , Aro forces resisted all axes strongly , although they lacked modern weapons . However , Arochukwu was captured on December 28 after four days of fierce battles in and around the city . As a result the Ibini Ukpabi shrine was allegedly blown up . Battles between British and Aro forces continued throughout the region until spring 1902 when Aro forces were defeated in the last major battle at Bende . The Aro Expedition ended three weeks later . Result of the war . Some of the Aro leaders like Okoro Toti , were arrested , tried by tribunals , and hanged . The Aro Confederacy was destroyed and Eze Kanu Okoro ( king of Arochukwu ) , went into hiding but was later arrested . Although Aro dominance crumbled in March 1902 , many Aros took part in later resistances against the British in the region such as in Afikpo ( 1902 – 1903 ) , Ezza ( 1905 ) , and other areas where the Aro had a particularly significant presence . The defeat of the Aro did help the British in their imperial agenda of conquest of the interior but serious opposition to British penetration in Igboland , however , clearly did not end with the Anglo – Aro War . In the years that followed , the British had to deal with many other conflicts and wars in various parts of Igboland such as the Nri Conflict ( 1905 – 1911 ) , Ekumeku War ( 1883 – 1914 ) , Igbo Women ' s War ( 1929 ) and etc .