of an Irish Republic. In the 1918 general election, Sinn Féin won 73 of Ireland's 105 seats, and in January 1919, its MPs assembled in Dublin and proclaimed themselves Dáil Éireann, the parliament of Ireland. The party supported the Irish Republican Army during the War of Independence, and members of the Dáil government negotiated the Anglo-Irish Treaty with the British government in 1921. In the Dáil debates that followed, the party divided on the Treaty. The pro-Treaty and anti-Treaty components (led by Michael Collins and Éamon de Valera respectively) managed to agree on a "Coalition Panel" of Sinn Féin candidates to stand in the 1922 general election. In the wake of the vote, anti-Treaty members walked out of the Dáil, and pro- and anti-Treaty members took opposite sides in the ensuing Civil War. In 1918 Sinn Féin member Constance Markievicz became the first woman elected to the United Kingdom House of Commons. However, in line with Sinn Féin abstentionist policy, she did not take her seat in the House of Commons. 1923–1970 Pro-Treaty Dáil deputies and other Treaty supporters formed a new party, Cumann na nGaedheal, on 27 April 1923 at a meeting in Dublin, where delegates agreed on a constitution and political programme. Cumann na nGaedheal went on to govern the new Irish Free State for nine years (it merged with two other organisations to form Fine Gael in 1933). Anti-Treaty Sinn Féin members continued to boycott the Dáil. At a special Ard Fheis in March 1926, de Valera proposed that elected members be allowed to take their seats in the Dáil if and when the controversial Oath of Allegiance was removed. When his motion was defeated, de Valera resigned from Sinn Féin; on 16 May 1926, he founded his own party, Fianna Fáil, which was dedicated to republicanising the Free State from within its political structures. He took most Sinn Féin Teachtaí Dála (TDs) with him. De Valera's resignation meant also the loss of financial support from America. The rump Sinn Féin party could field no more than fifteen candidates, and won only five seats in the June 1927 general election, a level of support not seen since before 1916. Vice-president and leader Mary MacSwiney announced that the party simply did not have the funds to contest the second election called that year, declaring "no true Irish citizen can vote for any of the other parties". Fianna Fáil