The Irish state came into being as the result of Irish partition in 1921 which divided the island of Ireland into Southern Ireland and Northern Ireland. In December 1922, the former seceded from the United Kingdom of Great Britain and Ireland to become the Irish Free State while the latter opted to remain within the United Kingdom. In December 1937 the state was renamed Ireland and on Easter Monday 1949 Ireland left the British Commonwealth to become a republic.

Irish independence from Britain in 1922 was preceded by the 1916 Easter Rising and the War of Independence, when Irish volunteers and the Irish Citizen Army took over sites in Dublin and Galway under terms expressed in the Proclamation of the Irish Republic. The seven signatories of this proclamation, Patrick Pearse, Thomas MacDonagh, Thomas Clarke, Sean MacDiarmada, Joseph Plunkett, Eamonn Ceannt and James Connolly, were executed by the British, along with nine others, and thousands were interned precipitating the Irish War of Independence.