Treacy, Seán (1895–1920), revolutionary, was born John Treacy on 14 February 1895 in Soloheadbeg, Co. Tipperary, son of Denis Treacy, farmer, and Bridget Treacy (née Allis). His father died when Treacy was three and the family went to live with his mother's brother, Jim Allis, in Lackenacreena, Hollyford, where he was educated at Hollyford national school and CBS Tipperary town. A prominent member of the Gaelic League in Tipperary town, he joined the IRB (1911), and in 1914, as a member of the Irish Volunteers, campaigned against recruitment for the British army. More interested in the military than the political side of the Irish revolution, in 1916 he tried unsuccessfully to join the Easter rising in Dublin and Galway, and was very disappointed by the failure of the insurrection outside Dublin. In 1916–17, along with Séamus Robinson (qv), he reorganised the Volunteers in Tipperary. His activities led to a six-month prison sentence in 1917, during which he was held in Cork, Mountjoy, and Dundalk. When he went on hunger strike, fears for his health led to his release under the cat-and-mouse act in November 1917. He was reimprisoned in Dundalk (February–June 1918), during which he undertook a ten-day hunger strike. In October 1918 he became vice-OC South Tipperary Brigade, preferring that the post of OC be given to Robinson. Along with Robinson, Seán Hogan (qv), and Dan Breen (qv), he was one of the ‘big four’ leaders of the IRA in Tipperary and was principally responsible for the killing of two RIC constables during an ambush to seize gelignite at Soloheadbeg on 21 January 1919, considered to be the first engagement of the war of independence. On 13 May 1919, in a successful effort to rescue Seán Hogan from police custody at Knocklong station, he shot dead two more constables and was himself shot in the throat and wounded, although not seriously. In autumn 1919 the ‘big four’ moved to Dublin, where they cooperated in the activities of Michael Collins (qv) and his ‘Squad’; they were involved in unsuccessful assassination attempts on the viceroy, Lord French (qv), and the chief secretary, Sir Ian Macpherson (qv). Returning to Tipperary in early 1920, they led attacks on RIC barracks throughout the county, before going back to Dublin in September 1920. On the night of 11 October, Treacy and Breen were discovered by crown forces at the home of Professor John Carolan at ‘Fernside’, Whitehall, north of Dublin city. They fought their way out of the house, but two British intelligence agents were killed, Breen was badly injured, and Carolan was killed for harbouring them. A few days later (14 October 1920), the Squad had plans to target senior British military personnel who were expected to attend the funeral of one of those shot at ‘Fernside’. When they did not appear, the Squad withdrew. However, Treacy had been spotted standing in the shop doorway of Peadar Clancy (qv) in Talbot St., and in an exchange of fire with British intelligence officers he and one of his assailants were shot dead. He had been due to marry his fiancée, May Quigley, on 25 October. He is buried in Kilfeacle graveyard, Co. Tipperary.
Desmond Ryan, Sean Treacy and the 3rd Tipperary Brigade (1945); Tim Pat Coogan, Michael Collins (1990); Joost Augusteijn, From public defiance to guerrilla warfare (1996)