Leader of Sinn Féin joined opposing sides with De Valera leading the Anti-Treaty faction, while Griffith joined the Pro-Treaty faction, which later became Cumann na nGaedheal. De Valera’ successor John J. O'Kelly was one of four leaders who served for brief periods of time as Sinn Féin’s party membership declined in favour of Fianna Fáil and Fine Gael. In 1937, Margaret Buckley became the first female President of Sinn Féin. During her thirteen years as leader, she vastly improved the relations between the IRA and the party. She was succeeded by Paddy McLogan and Tomás Ó Dubhghaill who both helped rebuild party support in
Fianna Éireann the Irish Free State in 1931. This was reversed when Fianna Fáil came to power in 1932, but re-introduced in 1938. During the splits in the Republican movement of the later part of the 20th century, the Fianna and Cumann na mBan supported Provisional Sinn Féin in 1969 and Republican Sinn Féin in 1986. The Fianna is a Proscribed Organisation in the United Kingdom under the Terrorism Act 2000. An earlier "Fianna" was organised "to serve as a Junior Hurling League to promote the study of the Irish Language" on 26 June 1902 at the Catholic Boys’ Hall, Falls Road,