Auxiliary Division in the context of "Irish Republican Army (1919–1922)"

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 Black and Tans (Irish: Dúchrónaigh) were constables recruited into the Royal Irish Constabulary (RIC) as reinforcements during the Irish War of Independence. Recruitment began in Great Britain in January 1920, and about 10,000 men enlisted during the conflict. The majority were unemployed former British soldiers from England, Scotland, and Wales who had fought in the First World War. Some sources count Irish recruits to the RIC from 1920 as "Black and Tans".

The Black and Tans had a reputation for brutality; they committed murder, arson, and looting and became notorious for reprisal attacks on civilians and civilian property. Their actions further swayed Irish public opinion against British rule and drew condemnation in Britain. The Black and Tans were sometimes confused with the Auxiliary Division, a counterinsurgency unit of the RIC, also recruited during the conflict and made up of former British officers. At the time, "Black and Tans" was sometimes used for both groups. Another force, the Ulster Special Constabulary (commonly called the "B-Specials"), was founded in 1920 to reinforce the RIC in Northern Ireland.