National Army (Ireland) in the context of "Battle of Dublin"

Michael Collins (Irish: Mícheál Ó Coileáin; 16 October 1890 – 22 August 1922) was an Irish revolutionary, soldier and politician who was a leading figure in the early-20th century struggle for Irish independence. During the War of Independence he was Director of Intelligence of the Irish Republican Army (IRA). He served in the government of the self-declared Irish Republic as the Minister for Home Affairs and later as the Minister for Finance. He was Chairman of the Provisional Government of the Irish Free State from January 1922 and commander-in-chief of the National Army from July until his death in an ambush in August 1922, during the Civil War.

Collins was born in Woodfield, County Cork, the youngest of eight children. He moved to London in 1906 to become a clerk in the Post Office Savings Bank at Blythe House. He was a member of the London GAA, through which he became associated with the Irish Republican Brotherhood and the Gaelic League. He returned to Ireland in January 1916 and fought in the Easter Rising. He was taken prisoner and held in the Frongoch internment camp as a prisoner of war, but he was released in December 1916.

The Irish Republican Army (IRA; Irish: Óglaigh na hÉireann, lit. 'warriors of Ireland') of 1922–1969 was a sub-group of the original pre-1922 Irish Republican Army, characterised as the Anti-Treaty IRA for its opposition to the Anglo-Irish Treaty. It existed in various forms until 1969, when the IRA split again into the Provisional IRA and Official IRA.

The original Irish Republican Army fought a guerrilla war against British rule in Ireland in the Irish War of Independence between 1919 and 1921. The Anglo-Irish Treaty signed on 6 December 1921 ended this war by granting most of the island a great degree of independence, but with six counties in the north staying within the United Kingdom as the new jurisdiction of Northern Ireland. The IRA units in the other 26 counties (that were to become the Irish Free State) split between supporters and opponents of the Treaty. The anti-Treatyites, sometimes referred to by Free State forces as "Irregulars", continued to use the name "Irish Republican Army" (IRA) or in Irish Óglaigh na hÉireann, as did the organisation in Northern Ireland, which originally supported the pro-Treaty side (if not the Treaty). Óglaigh na hÉireann was also adopted as the name of the pro-Treaty National Army, and it remains the official legal title of the Irish Defence Forces.