Under the Irish Republic's Dáil Constitution adopted in 1919, Dáil Éireann continued to exist after the Treaty. De Valera resigned the presidency and sought re-election (in an effort to destroy the Treaty just approved by the Dáil), but Arthur Griffith defeated him in the vote and assumed the presidency. (Griffith called himself President of Dáil Éireann rather than de Valera's more exalted President of the Republic.)
However that government or Áireacht had no legal status in British constitutional law, so another co-existent government emerged, in theory answerable to the House of Commons of Southern Ireland. Michael Collins became Chairman of the Provisional Government (i.e. prime minister). He also remained Minister for Finance of Griffith's republican administration. An example of the complexities involved can be seen even in the manner of his installation. In theory he was a Crown-appointed prime minister, installed under the Royal Prerogative. To be so installed, he had to formally meet the Lord Lieutenant of Ireland, Viscount Fitzalan of Derwent (the head of the British administration in Ireland). According to republican history, Collins met Fitzalan to accept the surrender of Dublin Castle, the seat of British government in Ireland. According to British constitutional theory, he met Fitzalan to 'kiss hands' (the formal name for the installation of a minister of the Crown), the fact of their meeting rather than the signing of any documents, duly installing him in office.
Anti-treatyites, having opposed the Treaty in the Dáil, withdrew from the assembly and, having formed an opposition 'republican government' under Eamon de Valera, began a campaign that led to the Irish Civil War. By mid-1922, Collins in effect laid down his responsibilities as President of the Provisional Government to become Commander-in-Chief of the National Army, a formal structured uniformed army that formed from the remnants of the Old IRA. As part of those duties, he travelled to his native Cork. En route home through County Cork on August 22, 1922, at Beal na mBlath (an Irish language term that means 'the Mouth of Flowers'), he was killed in an ambush, probably by a ricocheting bullet. He was not yet 32 years old.
After Collins's and Griffith's deaths in August 1922, W.T. Cosgrave became both Chairman of the Provisional Government and President of Dáil Éireann, and the distinction between the two became increasingly confused and irrelevant. In December 1922, both Southern Ireland and the Irish Republic were replaced by the Irish Free State, with executive authority nominally vested in the King, but exercised by a cabinet called the Executive Council, presided over by a prime minister called the President of the Executive Council.
Provisionalgovernments often occur as the result of a revolution or in wartime when an occupied nation or territory has been liberated or, conversely, when a government has been deposed by an invading army.
ProvisionalGovernment of the Republic of Korea (1919) - established in exile based in Shanghai, China and later in Chongqing, during the Japanese occupation of Korea.
Although not formally designated a "provisionalgovernment," the Second Continental Congress served as the de facto provisionalgovernment of the United States from the adoption of the Declaration of Independence in July 1776, until the ratification of the Articles of Confederation effective March 1, 1781.
The government, responsible to the lower house of the national legislature, is headed by the taoiseach, or prime minister.
Judicial authority in Ireland is vested in a supreme court, a high court, a court of criminal appeal, and circuit and district courts.
Republic of Ireland, On Easter Monday, April 18, 1949, by the terms of the Republic of Ireland Bill approved by the Dáil in November 1948, Eire became the Republic of Ireland, formally free of allegiance to the British crown and the Commonwealth of Nations.