1876 - 7 August 1942
He was not involved in the Easter Rising but in the aftermath he became one of the key figures in the resurgent Republican Movement. He was the main organiser of Count Plunkett’s by-election campaign in north Roscommon. This was the first of three by-election victories for Sinn Féin in 1917. In October of that year, O’Flanagan was elected vice-president of Sinn Féin.