Battle of Dublin The Battle of Dublin was a week of street battles in Dublin from 28 June to 5 July 1922 that marked the beginning of the Irish Civil War . It was fought between the forces of the new Provisional Government , which supported the Anglo - Irish Treaty , and a section of the Irish Republican Army ( IRA ) who opposed the Treaty . The fighting began with an assault by Provisional Government forces on the Four Courts building , which had been occupied by the Anti - Treaty IRA , and ended in a decisive victory for the Provisional Government . Background . On 14 April 1922 , about 200 anti - treaty IRA militants led by Rory O ' Connor occupied the Four Courts in Dublin , resulting in a tense stand - off . They wanted to spark a new armed confrontation with the British , which they hoped would bring down the Anglo - Irish Treaty , unite the two factions of the IRA against their former common enemy and thereby restart the fight to create an all - Ireland Irish Republic . At the time the British army still had thousands of soldiers concentrated in Dublin , awaiting evacuation . However , for those who were determined to make the Free State into a viable , self - governing Irish state , this was an act of rebellion that would have to be put down " by them " rather than by the British . The Provisional Government came under pressure from the British to take action against the Four Courts Garrison following the assassination of Sir Henry Wilson in London on 22 June 1922 , and when Free State Army General and Deputy Chief of Staff J . J . O ' Connell was arrested by Four Courts troops , the government decided to move against them . Collins accepted a British offer of artillery loaned by Winston Churchill for use by the new Irish Army , along with 200 from their store of 10 , 000 shells at Kilmainham , 3 miles away . It is possible that some British troops were also covertly loaned . Two 18 Pounder field guns were placed on Parliament Street and Winetavern Street , across the Liffey from the Four Courts complex , and after a final ultimatum they began their bombardment on 28 June . The assault on the Four Courts . Inside the building were twelve members of the Irish Republican Army Executive , including Chief - of - Staff Joe McKelvey , Director of Engineering Rory O ' Connor , and Quarter Master General Liam Mellows . The garrison consisted of roughly 180 men drawn from the 1st and 2nd Battalions of the IRA ' s 1st Dublin Brigade , commanded by Commandant Paddy O ' Brien , armed for the most part only with small arms , ( rifles , five Thompson submachinegun s and two Lewis light machine guns ) apart from one captured armoured car , which they named " The Mutineer " . The members of the IRA Army Executive were the political leaders of the garrison , but served as common soldiers under the command of Ernie O ' Malley , commander of the IRA ' s 2nd Southern Division . The Anti - Treaty side fortified the Four Courts to some extent , planting mines around the complex and barricading the doors and windows , but their leadership ordered them not fire first , to retain the moral high ground and so the Free State troops were allowed to surround the Four Courts . After the first day ' s bombardment proved ineffective , the British gave the Free State two more 18 pounder cannon , and offered 60 pounder howitzer s and even to bomb the Four Courts from the air . Collins turned down the latter two offers because of the risk of causing heavy civilian casualties . On the 29th , Free State troops stormed the eastern wing of the Four Courts , losing 3 killed and 14 wounded and taking 33 prisoners . The republicans ' armoured car , ' the Mutineer ' was also disabled and abandoned by its crew . Early the next day , Paddy O ' Brien was injured by shrapnel and Ernie O ' Malley took over military command in the Four Courts . By this time , the shelling had caused the Four Courts to catch fire . In addition , orders arrived from Oscar Traynor , the anti - treaty IRA commander in Dublin , for the Four Courts garrison to surrender , as he could not reach their position to help them . At 3 : 30pm on 30 June , O ' Malley surrendered the Four Courts to Brigadier General Paddy Daly , of the Free State ' s Dublin Guard unit . Three of the republican garrison had died in the siege Explosion in the Four Courts . Several hours before the surrender , at either 11 : 30 , or 2 : 15 the Irish Public Record Office located in the western block of the Four Courts , which had been used as an ammunition store by the Four Courts garrison , was the centre of a huge explosion , blowing to pieces one thousand years of Irish state and religious archives . Forty advancing Free State troops were badly injured . It was alleged by the National Army Headquarters that the Anti - treaty forces deliberately booby - trapped the Public Record office to kill advancing Free State troops . Tim Healy , a government supporter , later alleged that the explosion was the result of land - mines laid before the surrender , which exploded after the surrender . However , a study of the battle concluded that the explosion was caused by fires ignited by the shelling of the Four Courts , which eventually reached two truck loads of gelignite in the munitions factory . A towering mushroom cloud rose 200 feet over the Four Courts . Calton Younger ( 1968 ) identified 3 explosions ; " " . . two beneath the Records Office at about 2 . 15 " [ pm ] " and another at the back of the building at about 5 o ' clock . . " " At this stage in the war , troops on each side still had a sense of kinship with the other , as most of them had fought together in the Irish Republican Army during the Irish War of Independence . By appealing to friends on the Free State side , several anti - Treaty leaders among the Four Courts garrison , notably Ernie O ' Malley and Sean Lemass , escaped from captivity to continue fighting elsewhere . O ' Connell Street fighting . Despite the Free State force ' s success in taking the Four Courts , fighting continued in Dublin until 5 July . On the 29th anti - Treaty IRA units from the Dublin Brigade led by Oscar Traynor had occupied O ' Connell Street to try to distract Free State attention from their attack on the Four Courts . Not all of the IRA units in the capital were prepared to fight against the new Irish government however and their numbers were probably about 500 throughout the city . The republicans occupied the north eastern part of O ' Connell street , with their strongpoint at ' the block ' , a group of buildings which the Anti - Treatyites had connected by tunnelling through the walls . they had also taken over the adjoining Gresham , Crown , Granville , and Hammam Hotels . Their only position on the western side of the street was in the YMCA building . Additionally they had an outpost south of the Liffey at the Swan Pub on Aungier street . Oscar Traynor apparently hoped to receive reinforcements from the rest of the country but only Anti - Treaty units in Belfast and Tipperary replied and both of them arrived too late to take part in the fighting . The Provisional Government troops , commanded by general Tom Ennis started by clearing the outlying anti - treaty garrisons , which they had done by 1 July . They then drew a tighter cordon around O ' Connell street . Artillery was used to drive the Anti - Treaty fighters out of positions on Parnell street and Gardiner street , which gave the Free State troops a clear field of fire down O ' Connell street . The republican outpost in the YMCA was eliminated when Free State troops tunnelled underneath it and detonated a bomb . Traynor ' s men in " the block " held out until artillery was brought up , under the cover of armoured cars , to bombard them at point blank range . Incendiary bombs were also planted in the buildings . Oscar Traynor and most of his men ( 70 men and 30 women ) made their escape when the buildings they were holding caught fire . They mingled into civilian crowds and made their way to Blessington . Left behind was Republican leader Cathal Brugha and a rearguard of 15 men , who stayed behind in the Hamman hotel after Traynor and most other IRA men had left . At 5 pm on 5 July , when the fires made the hotel untenable , Brugha ordered his men to surrender . He however , stayed behind , only to emerge from the building alone , armed with a revolver . He was shot in the thigh when he left the burning building alone to confront the Free State troops and died later from blood loss . There were some further sporadic incidents of fighting around the city as Free State troops dispersed anti - treaty IRA groups . Cathal Brugha was the last casualty in the battle for Dublin which had cost both sides sixty - five killed and two hundred and eighty wounded . In addition , the Free State took over 400 Republican prisoners . The civilian casualties are thought to have numbered well over 250 . The high civilian casualties were doubtless the result of the use of heavy weapons , especially artillery , in a densely populated urban area . Aftermath . When the fighting in Dublin died down , the Free State Government was left firmly in control of the Irish capital and the anti - treaty forces dispersed around the country . " Round - ups " after the fighting captured more Republican prisoners and resulted in the death of prominent anti - Treaty activist Harry Boland who was shot dead in Skerries on 31 July . Oscar Traynor , Ernie O ' Malley and the other anti - Treaty fighters who had escaped the fighting in Dublin , regrouped in Blessington , around 30 km south west of the city . An anti - Treaty IRA force from county Tipperary had arrived there but was too late to participate in the Dublin fighting . Instead this force headed south and took a string of towns , including Enniscorthy and Carlow , but quickly abandoned them when faced with superior Free State forces . Most of the Republicans then retreated further south again to the so - called Munster Republic - territory south west of a line running from Limerick to Waterford . This in turn was taken by the Free State in an offensive from July to August 1922 . ( " See also Irish Free State offensive " ) . Four of the Republican leaders captured in the Four Courts , Rory O ' Connor , Liam Mellows , Joe McKelvey and Richard Barrett were later executed by the government in reprisal for the Anti - Treaty side ' s killing of TD ( member of Parliament ) Seán Hales . ( " see Executions during the Irish Civil War " ) . The street where Cathal Brugha was killed was later renamed Cathal Brugha street in his honour . Destruction of Irish historical records . On 22 June 1922 , in an attempt to dislodge Anti - Treaty forces holed up there , Pro - Treaty salvos launched into the complex housing stored Anti - Treaty munitions led to an enormous out - of - control fire . The massive conflagration spread rapidly , destroying the buildings and , with them , it led to the almost total destruction of the mass of Irish historical records archived in the Public Records Office of Ireland ( and in other parts of the Four Courts ) . As this closely followed the 1921 destruction of centuries of other important Irish record fonds kept in the Custom House , Dublin , the cumulative effect was the devastating annihilation of a huge swath of Ireland ' s historical resources , to the loss of all future researchers seeking to document many aspects of Irish history . Subsequent efforts by archivists and other interested parties have played an extremely important role in attempting to replace what was lost , but , though an impressive inventory of material has been amassed , continues to accumulate , and is now housed in the National Archives of Ireland , much of what was lost in the 1922 fire was irreplaceable . Which side bore the burden of the blame for the fire led to recriminations in the fire ' s aftermath , but the question of which side was ultimately responsible remains unresolved .