The plan for revolt was realised in the Easter Rising of 1916, in which the Volunteers, now explicitly declaring a republic, launched an insurrection whose aim was to end British rule and to found an Irish Republic. The rising, in which over four hundred people died, was almost exclusively confined to Dublin and was put down within a week, but the British response, executing the leaders of the insurrection and arresting thousands of nationalist activists, galvanised support for the separatist Sinn Féin – the party which the republicans first adopted and then took over. By now, support for the British war effort was on the wane, and Irish public opinion was shocked and outraged by some of the actions committed by British troops, particularly the murder of Francis Sheehy-Skeffington and the imposition of wartime martial law.
Secondly, the British, in the face of the crisis caused by the German Spring Offensive in April 1918, attempted to introduce conscription into Ireland combined with Home Rule outlined at the Irish Convention. This further alienated the Irish electorate and produced mass demonstrations during the Conscription Crisis of 1918. By the time of the General Election in December 1918, alienation from British rule was widespread.
To Irish Republicans, the Irish War of Independence had begun with the Proclamation of the Irish Republic during the Easter Rising of 1916.[6] Republicans argued that the conflict of 1919-21 (and indeed to some the subsequent Irish Civil War) was the defence of this Republic against attempts to destroy it.