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 Northern Ireland
The Troubles was a period of ethno-political conflict in Northern Ireland which spilled over at various times into England, the Republic of Ireland, and mainland Europe. The duration of the Troubles is conventionally dated from the late 1960s and considered by many to have ended with the Belfast "Good Friday" Agreement of 1998. Violence nonetheless continues on a sporadic basis.