Northern Ireland national football team
In 1920, Ireland was partitioned into Northern Ireland and Southern Ireland. In 1922, Southern Ireland gained independence as the Irish Free State, later to become a republic under the name of Ireland. Amid these political upheavals, a rival football association, the Football Association of Ireland, emerged in Dublin in 1921 and organised a separate league and international team. In 1923, at a time when the home nations had withdrawn from FIFA, the FAI was recognised by FIFA as the governing body of the Irish Free State on the condition that it changed its name to the Football Association of the Irish Free State. The Irish FA continued to organise its national team on an all-Ireland basis.
Ireland–United Kingdom relations
19th century violent and constitutional campaigns for autonomy or independence culminated in an election in 1918 returning almost 70% of seats to Sinn Féin, who declared Irish independence from Britain and set up a parliament in Dublin, and declared the independence of Ireland from the United Kingdom. A war of independence followed that ended with the Anglo-Irish Treaty of 1922, which partitioned Ireland between the Irish Free State, which gained dominion status within the British Empire, and a devolved administration in Northern Ireland, which remained part of the UK. In 1937, Ireland declared itself fully independent of the United Kingdom.