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 Ireland (1801–1923)
Ireland was part of the United Kingdom of Great Britain and Ireland from 1801 to 1922. For almost all of this period, the island was governed by the UK Parliament in London through its Dublin Castle administration in Ireland. Ireland faced considerable economic difficulties in the 19th century, including the Great Famine of the 1840s. The late 19th and early 20th centuries saw a vigorous campaign for Irish Home Rule. While legislation enabling Irish Home Rule was eventually passed, militant and armed opposition from Irish unionists, particularly in Ulster, opposed it. Proclamation was shelved for the duration following the outbreak of World War I. By 1918, however, moderate Irish nationalism had been eclipsed by militant republican separatism.