Partition of Ireland
Beginning on 21 January 1919 with the Soloheadbeg ambush, through the Irish War of Independence, Irish republicans attempted to bring about the secession of Ireland from the United Kingdom of Great Britain and Ireland. Meanwhile, Irish unionistsmost of whom lived in the northeast of the islandwere just as determined to maintain the Union. The British Government, committed to implementing Home Rule, set up a cabinet committee under the chairmanship of southern unionist Walter Long. The Long Committee recommended the establishment of two devolved administrations, dividing the island into two territories: Northern Ireland and Southern Ireland. This was implemented as the Government of Ireland Act 1920. The act entered into force as a "" on 3 May 1921 and provided that Northern Ireland would consist of the six northeastern counties, while the remainder of the island would form Southern Ireland. It was intended that each jurisdiction would be granted home rule but remain within the United Kingdom. The government of Southern Ireland never functioned: the war for independence continued until the two sides agreed a truce in July 1921, ending with the Anglo-Irish Treaty on 6 December 1921.
Irish Civil War
The fact that the Irish Civil War was fought between Irish Nationalist factions meant that the sporadic conflict in Northern Ireland ended. Collins and Sir James Craig signed an agreement to end it on 30 March 1922, but, despite this, Collins covertly supplied arms to the Northern IRA until a week before his death in August 1922. Because of the Irish Civil War, Northern Ireland was able to consolidate its existence and the partition of Ireland was confirmed for the foreseeable future. The continuing war also confirmed the northern Unionists' existing prejudices against the ethos of all shades of nationalism. This might have led to open hostilities between North and South had the Irish Civil War not broken out. Indeed, the Ulster Special Constabulary (the "B-Specials") that had been established in 1920 (on the foundation of Northern Ireland) was expanded in 1922 rather than being demobilised.