Sinn Féin 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 TDs with him.
Éamon de Valera nominally head of the anti-Treatyites, de Valera had little influence. He does not seem to have been involved in any fighting and had little or no influence with the military republican leadership - headed by IRA Chief of Staff, Liam Lynch. De Valera and the anti-Treaty TDs formed a "republican government" on 25 October 1922 from anti-Treaty TDs to "be temporarily the Supreme Executive of the Republic and the State, until such time as the elected Parliament of the Republic can freely assemble, or the people being rid of external aggression are at liberty to decide freely how they are