O'Hegarty, P[atrick] S[arsfield], (1879-1955), historian and bibliographer. Born in Carrignavar, Co. Cork, and educated by the Christian Brothers, he worked in the Post Office, resigning in 1918 when compelled to take the oath of allegiance. Author of studies of John Mitchel (1917) and Terence MacSwiney (1922) as well as bibliographies of Mangan, Allingham, and Joseph Campbell, he edited magazines including An tÉireannach for the Gaelic League (London), and The Irish World. His historical works Indestructible Nation (1918), The Victory of Sinn Féin (1924), and A History of Ireland under the Union, 1801-1922 (1952) reveal strong nationalist convictions.