Irish War of Independence

Between January 1919 and July 1921, the Irish Republican Army waged a guerrilla campaign against British rule in Ireland, while a breakaway Irish parliament tried to build the institutions of an independent state. Known too as the "Tan War" or the Anglo-Irish War, the conflict pitted the IRA against the British Army and the police, reinforced by the notorious Black and Tans and Auxiliaries. Roughly 2,300 people died. It ended in a truce and the Anglo-Irish Treaty, which created the Irish Free State while Northern Ireland stayed in the United Kingdom.

The Easter Rising of 1916 had been crushed, but the executions that followed and Britain's attempt to extend conscription to Ireland in 1918 swung opinion towards Sinn Féin. In the general election of December 1918 the party won 73 of Ireland's 105 seats. Refusing to sit at Westminster, its members met in Dublin as Dáil Éireann on 21 January 1919 and declared independence. The same day, IRA men acting without orders killed two police officers in an ambush at Soloheadbeg, County Tipperary, an event usually taken as the start of the war.

At first the IRA concentrated on seizing weapons and freeing prisoners, while the Dáil set up its own courts and raised money through a national loan organised by Michael Collins, its finance minister and the IRA's director of intelligence. Police were boycotted, and many remote barracks were abandoned. Although the IRA had a paper membership of over 100,000, Collins estimated that only about 15,000 were active, and perhaps 3,000 in the field at any one moment. The British government banned the Dáil in September 1919. From 1920 the IRA increasingly ambushed police and army patrols and attacked barracks, using small mobile "flying columns".

To bolster the Royal Irish Constabulary, Britain recruited thousands of former soldiers from Britain, nicknamed the Black and Tans after the colours of their uniforms, who began arriving in March 1920, followed by the Auxiliaries, made up of ex-officers. Both forces became notorious for indiscipline and reprisals against civilians, burning towns such as Balbriggan and destroying creameries and mills. By mid-1920 republicans controlled most county councils, and British authority had largely collapsed in the south and west.

The conflict intensified sharply in late 1920. Terence MacSwiney, Lord Mayor of Cork, died on hunger strike in a London prison in October. On Bloody Sunday, 21 November 1920, Collins's men killed British intelligence officers in Dublin; that afternoon police opened fire on spectators at a Gaelic football game at Croke Park and killed fourteen civilians. Seven days later, seventeen Auxiliaries died in an IRA ambush at Kilmichael in County Cork. Martial law was declared in four Munster counties on 10 December 1920, and that month British forces burned the centre of Cork city in reprisal for an ambush. The fighting was concentrated in Munster, especially County Cork, in Dublin and in Belfast.

In north-east Ulster, where most people were Protestant unionists, the conflict took on a sectarian character. A largely Protestant special constabulary was raised, loyalist paramilitaries retaliated against Catholics for IRA attacks, and nearly 500 people, mostly Catholics, were killed in Belfast. Under the Government of Ireland Act, Ireland was partitioned in May 1921 and Northern Ireland was created.

A ceasefire took effect on 11 July 1921. Negotiations led to the Anglo-Irish Treaty, signed on 6 December 1921, which ended British rule over most of the island. After a transitional period, the Irish Free State came into being on 6 December 1922 as a dominion governing itself. Disagreement among republicans over the Treaty led to the Irish Civil War in June 1922. In all, about 491 IRA members, more than 900 members of the British forces and around 900 civilians are estimated to have died.

Our 1914 map shows Ireland as part of the United Kingdom within the British Empire. Our 1930 map shows the island divided between the Irish Free State and Northern Ireland.