By 1923, the British Empire had reached its greatest extent. Between 1914 and 1918, the British had conquered extensive territories overseas and had kept most of these conquests after the Armistice in the form of League of Nations mandates. Even Britain’s colonies had acquired colonies: the Union of South Africa was administering what was formerly German South-West Africa, while Australia had taken control of what had been German New Guinea. And yet, paradoxically, by 1923 the victorious United Kingdom had lost more of its home territory than had the defeated German Reich. Most of Ireland had seceded from the UK and had become a self-governing dominion – the Irish Free State. Only the small province of Northern Ireland – comprising six of the nine counties of the ancient province of Ulster – remained part of the United Kingdom.[1] What is more, the Anglo-Irish Treaty that created the Free State was not imposed on the British by their victorious enemies. If anything, the reverse was true: Irish negotiators had signed the Treaty only after their British counterparts had threatened them with “immediate and terrible war” if they refused.[2]

These paradoxical developments were the final outcome of a dozen years of political and military conflict – the period of the Irish Revolution. Even before the Great War began, the United Kingdom had been shaken by conflict over the future of Ireland. Then, in 1916, Irish separatists had risen up in rebellion, proclaiming an Irish Republic. The rebels had been defeated and their leaders had been executed: but in the years that followed Irish public opinion had shifted in their favour. Once the war ended, Irish revolutionaries had declared their country’s independence and had launched a campaign of assassination, property destruction, and guerrilla warfare that had paralyzed the British administration in Ireland. The British government’s confused response to these developments had been too violent for moderate opinion to stomach, but not violent enough to suppress the insurgency. As a result, in 1921, the peace treaty had created an Irish dominion, from which the province of Northern Ireland had then withdrawn. This compromise had provoked a civil war in Ireland, but by 1923 the pro-Treaty side had emerged victorious and the partition of the country had become permanent.

The Origins of the Post-war Conflict, 1909-1914

Curiously, what had set Ireland smouldering in the years before the Great War was a stray spark from the Anglo-German naval arms race. In 1909, bad intelligence about German battleship building had caused a naval panic in the United Kingdom.[3] The British responded by building more battleships of their own, but this created a fiscal problem. Britain’s Liberal government had introduced old-age pensions that same year. In order to pay for both national and social security, the Chancellor of the Exchequer, David Lloyd George (1863-1945), introduced the People’s Budget. This covered the combined cost of social welfare and fleet expansion by raising taxes on the wealthy.

The People’s Budget caused a constitutional crisis. Against convention, it was rejected by the House of Lords, in which there was a large Conservative majority. Both parties denounced each other’s actions as revolutionary, and a general election was held in January 1910. This produced a hung parliament, but the minority Liberal government stayed in power with support from the Irish Parliamentary Party. The budget was passed, and a Parliament Bill was introduced to curb the power of the Lords. When the Lords rejected this bill, another general election was held in December 1910 and produced another hung parliament. Finally, in 1911, the new monarch, George V, King of Great Britain (1865-1936), promised to create as many new peers as necessary to pass the Parliament Bill. In the face of this threat, the House of Lords gave way and the Parliament Act of 1911 was passed. Under this new law, the Lords could no longer veto bills – only delay them for two years.[4]

But this result caused another, more serious constitutional crisis. Twice before, in 1886 and 1893, Liberal governments had introduced Home Rule Bills – legislation that would have meant limited self-government for Ireland. The First Home Rule Bill had been defeated in the House of Commons, and the Second had been vetoed by the Lords. Now, in 1912, the government introduced a Third Home Rule Bill – a bill that the Lords could no longer veto. Home Rule enjoyed the support of the majority of Irish people – the mostly Catholic descendants of the indigenous Irish. But even limited self-government was anathema to the mostly Protestant descendants of British colonists, who saw the Union with Great Britain as the safeguard of their rights and privileges. Opposition was fiercest in the northern province of Ulster, where Unionists pledged themselves to resist Home Rule by any means necessary. Between 1912 and 1914, British Conservatives delayed the passage of the Home Rule Bill through Parliament for as long as possible. They also supported a rebellion by Ulster Unionists, who raised a militia to resist Home Rule – the Ulster Volunteer Force (UVF). Convinced that the Liberal government would give in to this intimidation, Irish nationalists organized their own militia – the Irish Volunteers.[5]

By the summer of 1914, the Ulster Crisis had become acute. The passage of the Home Rule Bill could no longer be delayed, but the British government was wavering. In the so-called Curragh incident in March British army officers threatened to resign rather than impose Home Rule on Ulster. In June the UVF smuggled a shipment of rifles into the North and prepared to seize control of the province the moment Home Rule became law. When Irish Volunteers ran a boatload of guns into Howth Harbour in Dublin Bay, a clash between British troops and a crowd of civilians left four demonstrators dead. To many observers, it seemed that Ireland was on the verge of civil war. And then, on 24 July 1914, while a conference was being held at Buckingham Palace in search of a compromise, word arrived of the Austro-Hungarian ultimatum to Serbia.[6] The Ulster Crisis then dissolved into the July Crisis.

From Crisis to Insurrection, 1914-1917

The outbreak of war in Europe was greeted with a political truce in Great Britain and Ireland, just as it was elsewhere. The Home Rule Bill became law but was suspended for the duration of the war. Both the Irish Parliamentary Party and the Ulster Unionist Council supported the war effort and encouraged their Volunteers to enlist. Three divisions of the New Army were recruited in Ireland, and roughly equal numbers of Irish Volunteers and Ulster Volunteers enlisted in the Irish regiments of the British army. But the war had caused a split in the nationalist Volunteer movement. The majority (known as the National Volunteers) supported the Parliamentary Party, but within a year enthusiasm for the war had dwindled and recruitment had slowed down significantly. The party’s pro-war policy became even more unpopular after May 1915 when a coalition government was formed that included Conservative and Unionist ministers but no Irish nationalists. Without any clear purpose, and having lost their most active and committed members to the army, the National Volunteers eventually withered away.[7]

The minority Irish Volunteers, by contrast, had refused from the beginning to fight in what they regarded as a British war, and their numbers grew slowly as the war continued. In addition, the split had increased the influence of radical separatists within the movement. A secret “military council” of leading Volunteers laid plans for an armed insurrection and reached out to Imperial Germany for assistance. Then, at the eleventh hour, disaster struck. A shipload of German weapons and ammunition was lost at sea. The movement’s Chief of Staff, Eoin MacNeill (1867-1945), tried to stop the planned rebellion, calling it “madness”, but the military council decided to press on with whatever forces they could muster.[8]

On the morning of Easter Monday, 24 April 1916, the Irish Volunteers, along with elements of the socialist Irish Citizen Army, rose up in rebellion in Dublin, and, after seizing and fortifying positions in the centre of the city, proclaimed an independent Irish Republic. Once the British recovered from their surprise, they rushed in reinforcements and, after a week of heavy but sporadic fighting, the rebel forces were defeated by superior British numbers and firepower. By 30 April the rebels had surrendered. The few scattered uprisings outside of the capital did not last even that long.[9]

Casualties had not been particularly heavy, but over 500 civilians, rebels, and soldiers had been killed on the streets of Dublin – one of the UK’s major cities – and its centre had been badly damaged by artillery fire. The British response to the rebellion was also quite heavy-handed. Ireland was placed under martial law and fifteen leading rebels were condemned to death and executed by firing squad: only one rebel commander, Eamon de Valera (1882-1975), was spared. The authorities carried out mass arrests and over 3,000 known or suspected rebels were imprisoned. Many of these were soon released but approximately 1,400 were interned in a special camp at Frongoch, Wales.[10]

Yet the British response to the Rebellion of 1916 was not merely repressive. Lloyd George, who was Minister of Munitions in the coalition government, negotiated with both nationalists and Unionists, looking for a compromise that would make it possible to implement Home Rule without further delay. These negotiations came close to success: the leaders of both parties accepted Lloyd George’s proposal, which would have excluded six counties of Ulster from Dublin’s jurisdiction for the duration of the war. But this agreement was deliberately vague about what would happen after the war – and this vagueness made it possible for its enemies to wreck the deal. And though Lloyd George became Prime Minister in December 1916, the new coalition was dominated by his former political enemies, the Conservative party.[11]

From Insurrection to Insurgency, 1917-1919

Once anger over the loss of life and the destruction of property during the rebellion had subsided, Irish public opinion had turned in favour of the defeated rebels. This turn had been hastened, first by the executions of the captured leaders, and then by the failure of negotiations for Home Rule. By the middle of 1917, the previous year’s prisoners and internees had been set free, and were returning to Ireland, where they rejuvenated the Volunteer movement. The Parliamentary Party began to lose by-elections to Sinn Féin: this formerly minor party had benefited from being associated with the Easter Rising, and was attracting increasing support from disaffected nationalists. In June 1917, Eamon de Valera, who had just been released from prison in England, stood for election in East Clare and won with over 70 percent of the vote.[12]

Then, in the spring of 1918, the Germans launched their great offensive on the Western Front and everything began to change. In April 1918, the Lloyd George government introduced legislation to extend compulsory military service to Ireland. This inspired a mass anti-conscription movement, which was led by Sinn Féin but which united every shade of Irish nationalist opinion: and even though compulsory service was ultimately not imposed on Ireland, the political damage was irreversible. In the general election of December 1918, Sinn Féin swept most of Ireland’s constituencies outside of Ulster, winning seventy-three seats out of 105. Instead of taking their seats at Westminster, the Sinn Féin MPs established Dáil Eireann (Assembly of Ireland) as the parliament of the Irish Republic and declared their country’s independence from the United Kingdom. At the same time, however, British voters returned a large majority for the Lloyd George coalition. This result guaranteed that Ulster Protestant demands for special treatment would receive a more sympathetic hearing than Irish demands for independence.[13]

Throughout 1919, the campaign for an independent Irish Republic slowly gathered momentum. The Dáil adopted a constitution, elected Eamon de Valera as its president, and set about building an alternative state. At the same time, the Irish Volunteers began carrying out intermittent raids and ambushes, abandoning plans for a mass uprising in favour of guerrilla warfare. A new revolutionary leader, Michael Collins (1890-1922), emerged at the intersection of these two developments. As Teachta Dála (member of the Dáil, or TD) for South Cork and Minister for Finance, Collins collected and administered a National Loan; as Director of Organization and Intelligence for the Irish Volunteers, he spied on Dublin Castle and ordered the assassination of police detectives. The British government responded slowly to this growing challenge, though the Dáil was outlawed in September 1919, and both Sinn Féin and the Irish Volunteers were outlawed in November.[14]

The Irish War of Independence, 1920-1921

Unrest finally became open rebellion in the first six months of 1920. The most prominent representatives of the British state in Ireland, the armed Royal Irish Constabulary (RIC), came under increasing attack from the Irish Volunteers, who by now were generally known as the Irish Republican Army (IRA). Ambushes of police patrols and attacks on constabulary stations grew more frequent and more violent. The strength and morale of the RIC declined, as hundreds of constables quit the force and the remainder were concentrated in fewer, more defensible stations.[15] Sinn Féin won local government elections across the country, and both town and county councils proclaimed their allegiance to Dáil Eireann. More seriously, the revolutionaries undermined the British legal system: the Dáil established its own courts of justice and Volunteers acted as Republican police.[16]

Once again, the baffled British government’s response was ineffective. A new Home Rule Bill was introduced, which would create two devolved assemblies: one at Stormont for the six counties of Northern Ireland, which were dominated by Ulster Protestants, and one in Dublin for the remaining twenty-six counties; but this concession was widely seen as too little, too late. The Dublin Castle administration was reformed, but both its conciliatory gestures and its clumsy counterinsurgency campaign did nothing to slow the collapse of the British regime. By the summer of 1920, faced with a choice between crushing Ireland’s rebels by force, and offering the country dominion status, the Lloyd George government opted for increased repression.[17]

Thus, in the summer and autumn of 1920, the War of Independence entered its most notorious phase. The British government rushed emergency legislation through Parliament – the Restoration of Order in Ireland Act. The RIC was reinforced with large numbers of British ex-servicemen: ex-soldiers became ordinary constables, and were quickly nicknamed Black and Tans, while ex-officers joined a mobile and heavily-armed paramilitary gendarmerie, the Auxiliary Division.[18] Assisted by the military, the police went back on the offensive: but the IRA rose to the challenge. Ambushes of police and military patrols grew bloodier and more frequent, and, in retaliation, the police in particular took reprisals, looting and burning homes and shops and summarily executing suspects.[19] Meanwhile, as both sides fought a war of words for public opinion, in Parliament and in the press, their intelligence services played a deadly game of cat and mouse on the streets of Dublin.[20]

The disorder and violence peaked in late November. On the morning of 21 November 1920 – Bloody Sunday – the IRA assassinated fourteen known and suspected British intelligence agents in Dublin. That afternoon, during a raid on a Gaelic football match, Black and Tans opened fire on the crowd, killing fourteen civilians.[21] A week later, on 28 November, an IRA flying column in County Cork wiped out a platoon of ex-officer Auxiliaries, taking no prisoners.[22] Martial law was proclaimed in the southernmost counties – but on the evening of 10 December, before this proclamation came into effect, Auxiliaries went on a rampage in Cork City, burning public buildings and the city’s commercial centre in revenge for a bloody grenade attack on their comrades.[23]

The War of Independence continued for the first six months of 1921 – the bloodiest phase of the conflict. The police and military developed more effective counter-ambush tactics, and armoured their motor vehicles against rebel gunfire. In response, the guerrillas made increasing use of improvised explosive devices.[24] Both sides began attacking softer targets: extrajudicial killings by the Crown Forces became frequent, along with executions of known and suspected informers by the IRA.[25] In the midst of all this violence, the new Home Rule Bill was passed, and in May 1921, elections were held for the devolved assemblies of Northern and Southern Ireland. The results were predictable. In the North, Unionists won a majority, while in the South, Sinn Féin won almost every seat, and its members proclaimed the second Dáil Eireann.[26]

By the summer of 1921, however, both sides were tiring of the struggle and the recent elections gave them an unexpected and valuable opening to make peace. At Stormont, on 22 June 1921, the King opened the first session of the parliament of Northern Ireland with a conciliatory speech. This olive branch was well-received by the public, and Lloyd George persuaded his government to make an offer to negotiate. The revolutionaries accepted this offer. A truce was arranged, and the fighting stopped, across most of Ireland, on 10 July 1921.[27]

The Dáil sent a negotiating team to London, which included Michael Collins, and after weeks of hard bargaining the Irish representatives gave in to most of the British government’s demands. The Anglo-Irish Treaty, signed on 6 December 1921, created the Irish Free State, whose legislators would be required to swear an oath of fidelity to the British crown. The British army would withdraw from the territory of the Free State, which covered approximately four-fifths of the island, but the Free State’s own armed forces would be limited in size, and the Royal Navy would remain in control of three bases, two on the south coast and one in the northwest. Northern Ireland was given the choice to be part of this new dominion, or part of the United Kingdom. The day after the Treaty was signed, however, the province’s Unionist government chose the United Kingdom.[28]

Partition and Civil War, 1921-1923

The War of Independence had taken a rather different course in the North, due to the presence of the large Ulster Protestant community in the northeast.[29] In June 1920, rioting and street fighting had broken out in the city of Derry. In July 1920, a high-ranking RIC officer from the North had been assassinated in the South: his funeral was followed by anti-Catholic riots in several Northern towns. Then, on 21 July, loyalist mobs expelled thousands of Catholic workers from the shipyards and mills of Belfast. These expulsions were followed by days of sectarian rioting, in which many Catholics were burned out of their homes and shops and forced to flee south. The threat of even worse disorder in the North had been a factor in the British government’s introduction of the Restoration of Order in Ireland Act at the end of that month.[30]

The disturbances in the North then died down for a month, but flared up again towards the end of August: another assassination of a Northern RIC officer had triggered another anti-Catholic pogrom in the dead man’s home town, which had once again been followed by days of sectarian riots in Belfast. In response to Unionist demands for greater security, the British government authorised a new force of police, the Ulster Special Constabulary. Consisting of both full-time A Specials and part-time B Specials, this force was almost exclusively Protestant and sectarian and served only in the six counties that would become Northern Ireland.[31]

These additional security forces did not stop the violence: instead, the Northern conflict intensified in 1921. The new province of Northern Ireland included a large minority of Irish Catholics – a disloyal and alien fifth column, in the minds of Ulster Protestants. Though the King’s call for conciliation had been made at the opening of the Stormont parliament, the truce had little impact on the North. Indeed, 10 July 1921 became known as Belfast’s Bloody Sunday, after an ambush that killed a police constable was followed by riots that left sixteen civilians dead. Having liberated the rest of the country, the Northern IRA was determined to recapture the province, while Unionists were just as determined to make partition permanent. As a result, in the six counties, the bloodiest period of the Revolution was the six months following the signing of the Treaty in December 1921. In one particularly gruesome incident, on 23 March 1922, the killing of two special constables in Belfast was followed by the mass killing of six Catholic civilians, including five members of the McMahon family.[32]

Outside of Northern Ireland, however, the terms of the Anglo-Irish Treaty had split the Irish republican movement. In January 1922, the Dáil had ratified the Treaty by a vote of sixty-four to fifty-seven, and established a provisional government. But the compromise of dominion status was unacceptable to many revolutionaries. In March, an IRA convention rejected both the Treaty and the provisional government, and reaffirmed its loyalty to the Irish Republic. In April, anti-Treaty members of the IRA occupied the Four Courts, an important public building in Dublin, hoping to provoke a confrontation with the British. In June, the war-weary Irish people elected a new Dáil with a large pro-Treaty majority, but still the anti-Treaty faction would not compromise.[33] “The majority has no right to do wrong,” said a defiant Eamon de Valera, who opposed the Treaty.[34]

Finally, on 22 June 1922, civil war broke out in the Free State. Under pressure from the British to resolve the situation, the provisional government ordered its forces to attack the Four Courts, using field guns borrowed from the city’s remaining British garrison. A week of street fighting ended with pro-Treaty forces in control of the capital. Then, in July and August, the Free State’s forces launched a successful offensive, by land and sea, against Republican-held areas in the South and West.[35]

The defeated Republicans turned once again to guerrilla warfare.[36] One early casualty of this campaign was the pro-Treaty commander-in-chief, Michael Collins, who was ambushed and shot dead in County Cork on 22 August 1922.[37] Another casualty was the campaign to reconquer Northern Ireland, where the Unionist government gave itself emergency powers to stamp out what remained of the revolutionary insurgency.[38] The conflict in the Free State dragged on for months, but its ultimate outcome was never in doubt. The Republican commander-in-chief, Liam Lynch (1893-1923), was killed by Free State forces on 10 April 1923. The anti-Treaty IRA suspended operations on 30 April, but the desultory peace negotiations that followed came to nothing. In the end, on 24 May, instead of surrendering, the Republican forces were directed to simply cease fire, dump their weapons, and go home.[39]


When contrasted with revolutions in other parts of Europe during the post-war period, the human cost of Ireland’s revolution was relatively low. Peter Hart estimated that 3,269 people were killed and 4,318 wounded in Ireland between 1917 and 1923; the majority (70 percent) of these casualties occurred in 1921 and 1922.[40] Eunan O’Halpin has since determined that 2,141 people were killed in Ireland between 1917 and 1921; the majority (61 percent) of them lost their lives in 1921.[41] The bloodiest battlegrounds of the conflict were the southern province of Munster – especially County Cork – and the northern city of Belfast. But even at its worst, the violence was retail, not wholesale, and the revolution’s indecisive outcome reflected this dynamic.

In December 1921, both Michael Collins and Eamon de Valera had participated in the Treaty Debates in the Dáil. Collins had argued that the Treaty would give Ireland the freedom to achieve complete independence, while De Valera had predicted that it would not bring peace between Ireland and Britain. Ultimately, history would prove both men correct. In 1937, the Irish Free State adopted a new constitution, and became an independent republic for most practical purposes. Twelve years later, the restless dominion finally severed its remaining ties with the United Kingdom, left the Commonwealth, and became the Republic of Ireland. But still the anti-Treaty IRA persisted, underground, recognising itself alone as the legitimate government of Ireland, and launching sporadic attacks in the North. These attacks helped Ulster Protestants justify decades of discrimination against Northern Ireland’s Catholic minority. Finally, in 1969, fierce riots broke out once more in the cities of Derry and Belfast: the resulting conflict, colloquially known as the “Troubles”, would last until 1998. Even today, when the streets of Northern Ireland are mostly peaceful, and relations between the United Kingdom and the Republic of Ireland are relatively normal, political conflict continues over the character and future of this disputed province. The final chapter in the history of the Irish Revolution has not yet been written.

D.M. Leeson, Laurentian University

Section Editor: Edward Madigan