The Troubles
The Government of Ireland Act 1920 partitioned the island of Ireland into two separate jurisdictions, Southern Ireland and Northern Ireland, both devolved regions of the United Kingdom. This partition of Ireland was confirmed when the Parliament of Northern Ireland exercised its right in December 1922 under the Anglo-Irish Treaty of 1921 to ""opt out"" of the newly established Irish Free State. A part of the treaty signed in 1922 mandated that a boundary commission would sit to decide where the frontier of the northern state would be in relation to its southern neighbour. After the Irish Civil War of 1922–1923, this part of the treaty was given less priority by the new Dublin government led by W. T. Cosgrave, and was quietly dropped. As counties Fermanagh and Tyrone and border areas of Londonderry, Armagh, and Down were mainly nationalist, the Irish Boundary Commission could reduce Northern Ireland to four counties or less.
Foreign relations of Ireland
Since at least the 1600s Ireland has had political connections with the United Kingdom, with the whole island becoming a part of the United Kingdom of Great Britain and Ireland from 1801 to 1922. From the time of Ireland declaring itself independent from the United Kingdom in 1937, the two countries have been involved in a dispute over the status of Northern Ireland. Articles 2 and 3 of the Constitution of Ireland formerly claimed Northern Ireland as a part of the ""national territory"", though in practice the Irish government did recognise the UK's jurisdiction over the region.
From the onset of the Troubles in 1969, the two governments sought to bring the violence to an end. The Sunningdale Agreement of 1973 and the Anglo-Irish Agreement of 1985 were important steps in this process. In 1998, both states signed the Good Friday Agreement and now co-operate closely to find a solution to the region's problems. Articles 2 and 3 of the Constitution of Ireland were amended as part of this agreement, the territorial claim being replaced with a statement of aspiration to unite the people of the island of Ireland. As part of the Good Friday Agreement, the states also ended their dispute over their respective names: "Ireland" and the "United Kingdom of Great Britain and Northern Ireland". Each agreed to accept and use the others' correct name.