From the Act of Union on 1 January 1801, until 6 December 1922, the island of Ireland was part of the United Kingdom of Great Britain and Ireland. During the Great Famine, from 1845 to 1849, the island's population of over 8 million fell by 30%. One million Irish died of starvation and/or disease and another 1.5 million emigrated, mostly to the United States. This set the pattern of emigration for the century to come, resulting in a constant population decline up to the 1960s.
From 1874, and particularly under Charles Stewart Parnell from 1880, the Irish Parliamentary Party gained prominence. This was firstly through widespread agrarian agitation via the Irish Land League, that won land reforms for tenants in the form of the Irish Land Acts, and secondly through its attempts to achieve Home Rule, via two unsuccessful bills which would have granted Ireland limited national autonomy. These led to "grass-roots" control of national affairs, under the Local Government Act 1898, that had been in the hands of landlord-dominated grand juries of the Protestant Ascendancy.
Home Rule seemed certain when the Parliament Act 1911 abolished the veto of the House of Lords, and John Redmond secured the Third Home Rule Act in 1914. However, the Unionist movement had been growing since 1886 among Irish Protestants after the introduction of the first home rule bill, fearing discrimination and loss of economic and social privileges if Irish Catholics achieved real political power. In the late nineteenth and early twentieth century unionism was particularly strong in parts of Ulster, where industrialisation was more common in contrast to the more agrarian rest of the island. It was feared that any tariff barriers would heavily affect that region. In addition, the Protestant population was more prominent in Ulster, with a majority in four counties. Under the leadership of the Dublin-born Sir Edward Carson of the Irish Unionist Party and the Ulsterman Sir James Craig of the Ulster Unionist Party, unionists became strongly militant in order to oppose "the Coercion of Ulster". After the Home Rule Bill passed parliament in May 1914, to avoid rebellion with Ulster, the British Prime Minister H. H. Asquith introduced an Amending Bill reluctantly conceded to by the Irish Party leadership. This provided for the temporary exclusion of Ulster from the workings of the bill for a trial period of six years, with an as yet undecided new set of measures to be introduced for the area to be temporarily excluded.
Revolution and steps to independence
Though it received the Royal Assent and was placed on the statute books in 1914, the implementation of the Third Home Rule Act was suspended until after the First World War which defused the threat of civil war in Ireland. With hope of ensuring the implementation of the Act at the end of the war through Ireland's engagement in the war, Redmond and his Irish National Volunteers supported Britain and its Allies. 175,000 men joined Irish regiments of the 10th (Irish) and 16th (Irish) divisions of the New British Army, while Unionists joined the 36th (Ulster) divisions.
The remainder of the Irish Volunteers, who opposed any support of Britain, launched an armed insurrection against British rule in the 1916 Easter Rising, together with the Irish Citizen Army. This commenced on 24 April 1916 with the declaration of independence. After a week of heavy fighting, primarily in Dublin, the surviving rebels were forced to surrender their positions. The majority were imprisoned but fifteen of the prisoners (including most of the leaders) were executed as traitors to Britain. This included Patrick Pearse, the spokesman for the rising and who provided the signal to the volunteers to start the rising, as well as James Connolly, socialist and founder of the Industrial Workers of the World union and both the Irish and Scottish Labour movements. These events, together with the Conscription Crisis of 1918, had a profound effect on changing public opinion in Ireland.
In January 1919, after the December 1918 general election, 73 of Ireland's 106 Members of Parliament (MPs) elected were Sinn Féin members who refused to take their seats in the British House of Commons. Instead, they set up an Irish parliament called Dáil Éireann. This first Dáil in January 1919 issued a Declaration of Independence and proclaimed an Irish Republic. The Declaration was mainly a restatement of the 1916 Proclamation with the additional provision that Ireland was no longer a part of the United Kingdom. The new Irish Republic was recognised internationally only by the Russian Soviet Republic. The Irish Republic's Aireacht (Ministry) sent a delegation under Ceann Comhairle (Head of Council, or Speaker, of the Daíl) Seán T. O'Kelly to the Paris Peace Conference of 1919, but it was not admitted.
After the War of Independence and truce called in July 1921, representatives of the British government and the Irish treaty delegates, led by Arthur Griffith, Robert Barton and Michael Collins, negotiated the Anglo-Irish Treaty in London from 11 October to 6 December 1921. The Irish delegates set up headquarters at Hans Place in Knightsbridge and it was here in private discussions that the decision was taken on 5 December to recommend the treaty to Dáil Éireann. The Second Dáil Éireann narrowly ratified the Treaty.
In accordance with the treaty, on 6 December 1922 the entire island of Ireland became a self-governing dominion called the Irish Free State (Saorstát Éireann). Under the Constitution of the Irish Free State, the Parliament of Northern Ireland had the option to leave the Irish Free State one month later and return to the United Kingdom. During the intervening period, the powers of the Parliament of the Irish Free State and Executive Council of the Irish Free State did not extend to Northern Ireland. Northern Ireland exercised its right under the treaty to leave the new dominion and rejoined the United Kingdom on 8 December 1922. It did so by making an address to the King requesting, "that the powers of the Parliament and Government of the Irish Free State shall no longer extend to Northern Ireland." The Irish Free State was a constitutional monarchy sharing a monarch with the United Kingdom and other dominions of the British Commonwealth. The country had a governor-general (representing the monarch), a bicameral parliament, a cabinet called the "Executive Council", and a prime minister called the President of the Executive Council.
Irish Civil War
The Irish Civil War was the consequence of the creation of the Irish Free State. Anti-treaty forces, led by Éamon de Valera, objected to the fact that acceptance of the treaty abolished the Irish Republic of 1919 to which they had sworn loyalty, arguing in the face of public support for the settlement that the "people have no right to do wrong". They objected most to the fact that the state would remain part of the British Empire and that members of the Free State Parliament would have to swear what the Anti-treaty side saw as an oath of fidelity to the British King. Pro-treaty forces, led by Michael Collins, argued that the treaty gave "not the ultimate freedom that all nations aspire to and develop, but the freedom to achieve it".
At the start of the war, the Irish Republican Army (IRA) split into two opposing camps: a pro-treaty IRA and an anti-treaty IRA. The pro-treaty IRA disbanded and joined the new National Army. However, because the anti-treaty IRA lacked an effective command structure and because of the pro-treaty forces' defensive tactics throughout the war, Michael Collins and his pro-treaty forces were able to build up an army with many tens of thousands of World War I veterans from the 1922 disbanded Irish regiments of the British Army, capable of overwhelming the anti-treatyists. British supplies of artillery, aircraft, machine-guns and ammunition boosted pro-treaty forces, and the threat of a return of Crown forces to the Free State removed any doubts about the necessity of enforcing the treaty. The lack of public support for the anti-treaty forces (often called the Irregulars) and the determination of the government to overcome the Irregulars contributed significantly to their defeat.
Following a national referendum, on 29 December 1937 the new Constitution of Ireland (Bunreacht na hÉireann) came into force. This replaced the Constitution of the Irish Free State and called the state Ireland, or Éire in Irish. Articles 2 and 3 of the constitution asserted a nominal territorial claim over the whole island, considering the partition of Ireland under the 1922 Anglo-Irish Treaty illegitimate. The former Irish Free State government had taken steps to abolish the Office of Governor-General some months before the new Constitution came into force. Although the constitution established the office of President of Ireland, the question over whether Ireland was a republic remained open. Diplomats were accredited to the king, but the president exercised the internal functions of a head of state. For instance, the President gave assent to new laws with his own authority, without reference to King George VI who was only an "organ", that was provided for by statute law.
Ireland remained neutral during World War II, a period it described as the Emergency. Ireland's link with the Commonwealth was terminated with the passage of the Republic of Ireland Act 1948, which came into force on 18 April 1949 and declared that the state was a republic. At the time, a declaration of a republic terminated Commonwealth membership. This rule was changed 10 days after Ireland declared itself a republic, with the London Declaration of 28 April 1949. Ireland did not reapply when the rules were altered to permit republics to join. Later, the Crown of Ireland Act was repealed in Ireland by the Statute Law Revision (Pre-Union Irish Statutes) Act, 1962.
Ireland became a member of the United Nations in December 1955, after having been denied membership because of its neutral stance during the Second World War and not supporting the Allied cause. At the time, joining the UN involved a commitment to using force to deter aggression by one state against another if the UN thought it was necessary.
Interest towards membership of the European Economic Community (EEC) developed in Ireland during the 1950s, with consideration also given to membership of the European Free Trade Area. As the United Kingdom intended on EEC membership, Ireland applied for membership in July 1961 due to the substantial economic linkages with the United Kingdom. However, the founding EEC members remained skeptical regarding Ireland's economic capacity, neutrality, and unattractive protectionist policy. Many Irish economists and politicians realised that economic policy reform was necessary. The prospect of EEC membership became doubtful in 1963 when French President General Charles de Gaulle stated that France opposed Britain's accession, which ceased negotiations with all other candidate countries. However, in 1969 his successor, Georges Pompidou, was not opposed to British and Irish membership. Negotiations began and in 1972 the Treaty of Accession was signed. A referendum held in 1972 confirmed Ireland's entry, and it finally joined the EEC in 1973.
The economic crisis of the late 1970s was fuelled by the Fianna Fáil government's budget, the abolition of the car tax, excessive borrowing, and global economic instability including the 1979 oil crisis. There were significant policy changes from 1989 onwards, with economic reform, tax cuts, welfare reform, an increase in competition, and a ban on borrowing to fund current spending. This policy began in 1989–1992 by the Fianna Fáil/Progressive Democrat government, and continued by the subsequent Fianna Fáil/Labour government and Fine Gael/Labour/Democratic Left government. Ireland became one of the world's fastest growing economies by the late 1990s in what was known as the Celtic Tiger period, which lasted until the global Financial crisis of 2007–08. However, since 2014, Ireland has experienced strong economic growth.
In the Northern Ireland question, the British and Irish governments started to seek a peaceful resolution to the violent conflict involving many paramilitaries and the British Army in Northern Ireland known as "The Troubles". A peace settlement for Northern Ireland, known as the Good Friday Agreement, was approved in 1998 in referendums north and south of the border. As part of the peace settlement, the territorial claim to Northern Ireland in Articles 2 and 3 of the Constitution of Ireland was removed by referendum. In its white paper on Brexit the United Kingdom government reiterated its commitment to the Good Friday Agreement. With regard to Northern Ireland's status, it said that the UK Government's "clearly-stated preference is to retain Northern Ireland’s current constitutional position: as part of the UK, but with strong links to Ireland".