Irish Republic the Third Dáil, and all future institutions arising from it, as illegal. (See Second Dáil). The anti-Treaty side was then defeated in the Civil War. Most militant opposition to the Free State came to an end on 24 May 1923 when Frank Aiken, chief-of-staff of the IRA issued the order to "dump arms" and Éamon de Valera issued his address to the "Legion of the Rearguard". Éamon de Valera continued as president of the Sinn Féin political party. In March 1926, Éamon de Valera, along with most anti-Treaty politicians, founded a new party called 'Fianna Fáil' and ended their boycott
Éamon de Valera the work of Michael Collins and based on three sources: British oaths in the dominions, the oath of the Irish Republican Brotherhood and a draft oath prepared by de Valera in his proposed Treaty alternative, "Document No. 2"). De Valera began a legal case to challenge the requirement that members of his party take the Oath, but the assassination of the Vice-President of the Executive Council (deputy prime minister) Kevin O'Higgins on 10 July 1927 led the Executive Council under W. T. Cosgrave to introduce a Bill on 20 July requiring all Dáil candidates to promise on oath that if