Irish Republican Army

The Irish Republican Army (IRA) (Irish: Óglaigh na hÉireann) was an Irish republican revolutionary military organisation. It was descended from the Irish Volunteers, an organisation established on 25 November 1913 that staged the Easter Rising in April 1916. In 1919, the Irish Republic that had been proclaimed during the Easter Rising was formally established by an elected assembly (Dáil Éireann), and the Irish Volunteers were recognised by Dáil Éireann as its legitimate army. Thereafter, the IRA waged a guerrilla campaign against British rule in Ireland in the 1919–21 Irish War of Independence.

Following the signing in 1921 of the Anglo-Irish Treaty, which ended the War of Independence, a split occurred within the IRA. Members who supported the treaty formed the nucleus of the Irish National Army founded by IRA leader Michael Collins. However, much of the IRA was opposed to the treaty. The anti-treaty IRA fought a civil war with their former comrades in 1922–23, with the intention of creating a fully independent all-Ireland republic. Having lost the civil war, this group remained in existence, with the intention of overthrowing both the Irish Free State and Northern Ireland and achieving the Irish Republic proclaimed in 1916.