This led to the Irish Civil War, fought between the new Free State forces, composed of pro-treaty IRA men and others ( including thousands of veterans of the First World War ), and the majority of the old IRA, led by Liam Lynch, who rejected the Treaty.

The Irish Civil War began on the 28 June 1922 between the Republican Anti-treaty IRA and the newly-recruited pro-treaty National Army.

Many of Dublin's finest buildings were destroyed at this time ; the historic General Post Office ( GPO ) was a bombed out shell after the 1916 Rising ; James Gandon's Custom House was burned by the IRA in the War of Independence, while one of Gandon's surviving masterpieces, the Four Courts had been seized by republicans and bombarded by the pro-treaty army.

The conclusion of the pro-treaty, anti-treaty Irish Civil War confirmed its status — the state became the present republic Ireland in 1937.

He fought in the 1916 Easter Rising, served as Chief of Staff of the Irish Republican Army during the War of Independence and became commander of the pro-treaty forces in the Irish Civil War after the death of Michael Collins.

The pistol had been a gift from Michael Collins while the two men had been on the same side, indeed, were friends, before Collins became head of the pro-treaty Provisional Government.

Griffith and Collins died in August 1922 during the early stages of the Irish Civil War, leaving Cosgrave to lead the pro-treaty faction and the Provisional Government in the run-up to the formal establishment of the Irish Free State.

Though the treaty was narrowly ratified, the split led to the Irish Civil War, which was ultimately won by the pro-treaty side.

O ' Connell Street was again the scene of a pitched battle in July 1922, on the outbreak of the Irish Civil War, when anti-treaty fighters under Oscar Traynor occupied the street after pro-treaty Irish National Army troops attacked the republican garrison in the nearby Four Courts.

In the Irish Civil War of 1922 – 1923, he took the pro-treaty side and was made Director of Intelligence, replacing Liam Tobin.

However, the draft constitution of the Irish Free State was then published on 15 June, and so the anti-treaty Sinn Féin group's 36 seats out of 128 seemed to many to be a democratic endorsement of the pro-treaty Sinn Féin's arrangements.

This boycott gave uncontested control to the pro-treaty members of Sinn Féin, and so enabled W. T. Cosgrave to establish the Second Irish Provisional Government and later the First Executive Council of the Irish Free State.

The pro-treaty wing of Sinn Féin had decided to formally break off and become a distinct party in late December 1922, but its formal launch was delayed until after the New Year as a direct consequence of the turmoil caused by the civil war.

Opponents pointed out that leading pro-treaty politicians had admitted if referendums had been held in countries other than Ireland, it would probably have been defeated there as well.

Although a senior figure on the " pro-treaty " side of Ireland's political divide, Desmond FitzGerald had remained friendly with anti-Treaty republicans such as Belfast man Seán MacEntee, a minister in Éamon de Valera's government, and father-in-law of Conor Cruise O ' Brien.

They contrasted his continuing bitterness towards Blythe with the cross party friendships of their colleagues Seán MacEntee ( anti-treaty ) and Desmond FitzGerald ( pro-treaty ) who after the divide re-established relationships and ensured their children held no civil war bitterness.

In 1989 pro-treaty groups organized as the Midwest Treaty Network in support of the Ojibwe fishing families.

The pro-treaty side won a majority of seats and the anti-treaty faction boycotted the assembly, refusing to recognise the body as the legitimate heir to the Second Dáil, and the Civil War broke out shortly afterwards.

The election was effectively a referendum on the Anglo-Irish Treaty in the southern partition of Ireland but the pro-treaty members of Sinn Féin won a majority of seats.

As in the 1921 elections, Sinn Féin stood one candidate for every seat, except those for the University of Dublin and one other ; however the treaty had divided the party between 65 pro-treaty candidates, 57 anti-treaty and 1 nominally on both sides.

They agreed that the pro-treaty and anti-treaty factions would fight the general election jointly and form a coalition government afterwards.

They soon gained a reputation for brutality, as the RIC campaign against the IRA and Sinn Féin members was stepped up and police reprisals for IRA attacks were condoned by the government.

" However he was soon to begin negotiations with IRA leaders to recognise their authority and end the conflict.

By the time of the 1997 general election Sinn Féin stated that they would prefer a Fianna Fáil led government and the IRA resumed their ceasefire soon after Fine Gael lost the 1997 general election.

In March 1921 at Crossbarry in County Cork the Essex regiment encircled the IRA " West Cork Flying Column " with 1, 200 troops and soon managed to flush out a company sized element of the IRA.

Both the IPLO and the IPLOBB were soon ended by the Provisional IRA in November 1992.

On 10 August Bombardier Paul Challenor became the first soldier to be killed by the Provisional IRA in Derry, when he was shot by a sniper on the Creggan estate.

It was only after the Provisional IRA declared a ceasefire in 1994 that the Continuity IRA became active, announcing its intention to continue the campaign against British rule.

On the day Mountbatten was assassinated the IRA ambushed and killed eighteen British Army soldiers, sixteen of them from the Parachute Regiment at Warrenpoint, County Down, in what became known as the Warrenpoint ambush.

With the advent of a Provisional IRA ceasefire and the beginning of what became known as the Peace Process during the 1990s, the official view of the Rising became more positive and in 1996 an 80th anniversary commemoration at the Garden of Remembrance in Dublin was attended by the Taoiseach and leader of Fine Gael, John Bruton.

This convention, that subsequently became known as an IRA convention, was called to coincide with the Sinn Féin party conference.

Adams ( allegedly ) rose to become the most senior figure in the IRA Northern Command on the basis of his absolute rejection of anything but military action, but this conflicts with the fact that during his time in prison, Adams came to reassess his approach and became more political.

Eventually, the IRA became the American Amateur Racquetball Association ( AARA ); in late 1995, it renamed itself as the United States Racquetball Association ( USRA ).

The behaviour of both groups immediately became controversial ( one major critic was King George V ) for their brutality and violence, not just towards IRA suspects and prisoners but towards Irish people in general.

On 27 November 1975, McWhirter was assassinated by two IRA volunteers, both of whom were members of what became known as the Balcombe Street Gang, the group for whose capture McWhirter had offered the reward.

He later became an IRA advisor to the IRA Executive during the 1950s Border Campaign.

In March 1919 he became IRA chief of staff, a position he held until January 1922.

McBride worked as a journalist in Paris and London before returning to Dublin in 1927, when he became Director of Intelligence of the IRA.

Although it was a non-military organisation, Saor Éire was declared unlawful, along with the IRA, Cumann na mBan and nine other bodies, while MacBride became public enemy number one of the State security services.

In 1936, the Chief of staff of the IRA, Moss Twomey was sent to prison for three years, and MacBride became chief of staff, at a time when the movement was in a state of disarray, with several factions and personalities conflicting.

In what became known as the Arms Crisis, two ministers, Charles Haughey and Neil Blaney were sacked from the government for gun-running for the Provisional IRA in May 1970.

O ' Duffy was the leader of the Monaghan Brigade of the Irish Republican Army ( IRA ) during the successful Irish War of Independence and in this capacity became Chief of Staff of the IRA in 1922.

In January of the following year he became IRA Chief of Staff, replacing Richard Mulcahy.

Wilson became increasingly concerned that Tudor, with the connivance of Lloyd George, who loved to drop hints to that effect, was operating an unofficial policy of killing IRA men in reprisal for the deaths of pro-Crown forces.

Following these moves, the IRA became increasingly active in disrupting the activities of the opposition party, Cumann na nGaedheal.

The respective camps became known as ' Provisional Army Council ' and Sinn Féin / Provisional IRA, while those remaining became known as Official Sinn Féin / Official IRA.