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 and Collins would later become opponents during the Irish Civil War. In January 1921, in his first appearance in the Dáil, after his return to a country gripped by the War of Independence, de Valera introduced a motion calling on the IRA to desist from ambushes and other tactics that were allowing the British to successfully portray it as a terrorist group, and to take on the British forces with conventional military methods. This they strongly opposed, and de Valera relented, issuing a statement expressing support for the IRA, and claimed it was fully under the control of the Dáil.