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 In 1923, at a time when the home nations had withdrawn from FIFA, the FAI was recognised by FIFA as the governing body of the Irish Free State on the condition that it changed its name to the Football Association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.
Irish issue in British politics
The Anglo-Irish War was fought between the forces of the provisional government of the Irish Republic and Britain, between January 1919 and July 1921. The British tried repressive force but the IRA under Michael Collins used about 3,000 fighters in asymmetric warfare. Prime Minister David Lloyd George presided over the Government of Ireland Act 1920 which partitioned Ireland into Southern Ireland and Northern Ireland in May 1921 during the Anglo-Irish War. Lloyd George used the threat of a massive war to force the Collins and his Irish negotiators to agree to the peace treaty in December 1922. It created a largely autonomous dominion, the Irish Free State, to replace the (failed) Southern Ireland. Meanwhile Northern Ireland, or Ulster, (with home rule) remained part of the United Kingdom. The Dail majority supported Collins and the treaty, but De Valera, President of the Dail, rejected it. De Valera led a civil war in Ireland that failed. The treaty with Britain went into effect and Northern Ireland remained with the UK.