Republic of Ireland–United Kingdom border
Originally intended as an internal boundary within the United Kingdom of Great Britain and Ireland, the border was created in 1921 under the United Kingdom Parliament's Government of Ireland Act 1920. Prior to this, a separatist Irish parliament had been established in Dublin, which did not recognise the Government of Ireland Act, and was actively engaged in the Irish War of Independence. The Act was intended to deliver Home Rule in Ireland, with separate parliaments for Southern Ireland (which included three of the nine counties of Ulster) and Northern Ireland. Six of the thirty-two counties of Ireland were assigned to Northern Ireland, and the rest of Ireland comprising 26 counties to Southern Ireland.
History of the Orange Institution
The Fourth Home Rule Act was passed as the Government of Ireland Act 1920, the north eastern part of Ulster being partitioned from Southern Ireland as Northern Ireland. This new self-governing entity within the United Kingdom was confirmed under the terms of the Anglo-Irish Treaty of 1921. Southern Ireland became the Irish Free State in December 1922, then, in December 1937, it became Éire. This independent Irish state has been popularly known (in English) as the Republic of Ireland since it left the Commonwealth in April 1949.