Partition of Ireland

(1949) The division of Ireland between an independent Irish Republic and Northern Ireland (Ulster), where the Protestant majority wanted to remain British. The Ulster Plantation in the 17th-c had established a Protestant ascendancy over the native Catholic population. A partition movement arose during the 1880s series of Home Rule Bills. Increased support for Sinn Féin followed the Easter Rising (1916), and the IRA's guerrilla campaign spread to Ulster. Protestant attacks in Catholic areas of Ulster caused deaths as well as retaliations by the IRA. The Anglo-Irish Treaty (1921) established an Irish Free Sate that excluded the six counties of Ulster. The formation of an independent Republic of Ireland in 1949 led to Britain guaranteeing Northern Ireland the status of a self-governing province of the UK, as long as this was supported by a majority vote in the Northern Ireland parliament (Stormont).

The Partition of Ireland took place in May 1921, following the enactment of the Government of Ireland Act 1920 and ratification of the Anglo-Irish Treaty that ended the Anglo-Irish War.

The Government of Ireland Act 1914, which was never implemented, would have given home rule to the island of Ireland, but six counties in Ulster were to be excluded "temporarily" from the territory of the new Irish parliament and government and to continue to be governed as before from Westminster and Whitehall. The Government of Ireland Act 1920 created two Home Rule parliaments: a Parliament of Northern Ireland which functioned and a Parliament of Southern Ireland which did not.

While the Partition of Ireland came to be one of the most contentious issues in Anglo-Irish relations and in the internal politics of both Northern Ireland and the Irish Free State and its successor states, it was not the most controversial aspect of the Anglo-Irish treaty in the Irish Free State in 1921. Most leaders in the south of Ireland, both pro- and anti-Treaty, assumed that the commission would award largely nationalist areas such as County Fermanagh, County Tyrone, South Derry, South Armagh and South Down, and the City of Derry to the Free State, and that the remnant of Northern Ireland would not be economically viable and would eventually opt for union with the rest of the island as well.

Later, the new Constitution of Ireland in 1937 and the declaration of the Republic of Ireland in 1949, when combined with the UK responses, tended to reinforce the feeling of partition.