Anglo-Irish Treaty

The 1921 Anglo-Irish Treaty, known in Ireland as the Treaty and officially as the Articles of Agreement for a Treaty Between Great Britain and Ireland, was an agreement between the government of the United Kingdom and the government of the Irish Republic that concluded the Irish War of Independence. It provided for the establishment of the Irish Free State within a year as a self-governing dominion within the British Empire, with a status equal to that of the Dominion of Canada. It also gave Northern Ireland, created by the Government of Ireland Act 1920, the option to opt out of the Irish Free State, an option the Parliament of Northern Ireland exercised.