Partition of Ireland
The partition of Ireland () divided the island of Ireland into two distinct jurisdictions, Northern Ireland and Southern Ireland. It took place on 3 May 1921 under the Government of Ireland Act 1920. Today the former is still known as Northern Ireland and forms part of the United Kingdom, while the latter is now a sovereign state also named Ireland and sometimes called the Republic of Ireland.
Northern Ireland
Events overtook the government. The pro-independence Sinn Féin won 73 of the 105 parliamentary seats in Ireland at the general election of 1918, and unilaterally established the First Dáil, an extrajudicial parliament in Ireland. Ireland was partitioned between Northern Ireland and Southern Ireland in 1921, under the terms of Lloyd George's Government of Ireland Act 1920, during the Anglo-Irish War between Irish republican and British forces. A truce was established on 11 July; the war ended on 6 December 1921 with the signing of the Anglo-Irish Treaty, which created the Irish Free State. Under the terms of the treaty, Northern Ireland would become part of the Free State unless the government opted out by presenting an address to the king, although in practice partition remained in place.