Ulster Special Constabulary in the context of "Black and Tans"

The Irish War of Independence (Irish: Cogadh na Saoirse), also known as the Anglo-Irish War, was a guerrilla war fought in Ireland from 1919 to 1921 between the Irish Republican Army (IRA, the army of the Irish Republic) and British forces: the British Army, along with the quasi-military Royal Irish Constabulary (RIC) and its paramilitary forces the Auxiliaries and Ulster Special Constabulary (USC). It was part of the Irish revolutionary period.

In April 1916, Irish republicans launched the Easter Rising against British rule and proclaimed an Irish Republic. Although it was defeated after a week of fighting, the Rising and the British response led to greater popular support for Irish independence. In the December 1918 election, republican party Sinn Féin won a landslide victory in Ireland. On 21 January 1919 they formed a breakaway government (Dáil Éireann) and declared Irish independence. That day, two RIC officers were killed in the Soloheadbeg ambush by IRA volunteers acting on their own initiative. The conflict developed gradually. For most of 1919, IRA activity involved capturing weaponry and freeing republican prisoners, while the Dáil set about building a state. In September, the British government outlawed the Dáil throughout Ireland, Sinn Féin was proclaimed (outlawed) in County Cork and the conflict intensified. The IRA began ambushing RIC and British Army patrols, attacking their barracks and forcing isolated barracks to be abandoned. The British government bolstered the RIC with recruits from Britain—the Black and Tans and Auxiliaries—who became notorious for ill-discipline and reprisal attacks on civilians, some of which were authorised by the British government. Thus the conflict is sometimes called the "Black and Tan War". The conflict also involved civil disobedience, notably the refusal of Irish railwaymen to transport British forces or military supplies.

The Ulster Volunteers was an Irish unionist, loyalist paramilitary organisation founded in 1912 to block domestic self-government ("Home Rule") for Ireland, which was then part of the United Kingdom. The Ulster Volunteers were based in the northern province of Ulster. Many Ulster Protestants and Irish unionists feared being governed by a nationalist Catholic-majority parliament in Dublin and losing their links with Great Britain. In 1913, the militias were organised into the Ulster Volunteer Force (UVF) and vowed to resist any attempts by the British Government to impose Home Rule on Ulster. Later that year, Irish nationalists formed a rival militia, the Irish Volunteers, to safeguard Home Rule. In April 1914, the UVF smuggled 25,000 rifles into Ulster from Imperial Germany. The Home Rule Crisis was interrupted by the First World War. Much of the UVF enlisted with the British Army's 36th (Ulster) Division and went to fight on the Western Front.

After the war, the British Government decided to partition Ireland into two self-governing regions: Northern Ireland (which overall had a Protestant/unionist majority) and Southern Ireland. However, by 1920 the Irish War of Independence was raging and the Irish Republican Army (IRA) was launching attacks on British forces in Ireland. In response, the UVF was revived. It was involved in some sectarian clashes and minor actions against the IRA. However, this revival was largely unsuccessful and the UVF was absorbed into the Ulster Special Constabulary (USC), the new reserve police force of Northern Ireland.