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.
Partitionism
When the island was partitioned in 1921, thousands of Irish Catholics and nationalists were left "stranded" in the "Protestant, Pro-British state" of Northern Ireland. Some nationalists have described partitionism as the belief that "Ireland" and "Irishness" is confined to the Republic of Ireland. For example, during a debate in the Dáil on 9 March 1999, Austin Currie denounced those in the Republic of Ireland who questioned the Irishness of "northern" Catholics: