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 by historians as a positive one, and a biography by Tim Pat Coogan alleges that his failures outweigh his achievements, with de Valera's reputation declining while that of his great rival in the 1920s, Michael Collins, is rising.The most recent work on de Valera by historian Diarmaid Ferriter presents a more positive picture of de Valera's legacy. Bertie Ahern, at a book launch for Diarmaid Ferriter's biography of de Valera, described de Valera's achievements in political leadership during the formative years of the state: One of de Valera's finest hours was his regrouping of the Republican side after defeat in