The Anglo-Irish Treaty was an agreement signed in London on 6 December 1921 between the government of the  United Kingdom of Great Britain and Ireland  and representatives 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 "community of nations known as the British Empire", a status "the same as that of the Dominion of Canada". It also provided Northern Ireland, which had been created by the Government of Ireland Act 1920, an option to opt out of the Irish Free State, which it exercised.

The Irish delegates were Arthur Griffith, Edmund Duggan, Michael Collins, Robert Barton, and George Gavin Duffy.

Éamon de Valera called a cabinet meeting to discuss the treaty on 8 December1921. The cabinet decided by four votes to three to recommend the treaty to Dáil Eireann on December 14. The contents of the treaty divided the Irish Republic's leadership, with…