Ó Fiaich, Tomás (1923–90), cardinal archbishop of Armagh, was born 3 November 1923 at Anamar, Cullyhanna, Co. Armagh, as Thomas James Fee, second son of Patrick Fee (1882–1964) and Annie Fee (née Carragher; d. 1932). Both parents taught at Cregganduff public elementary school: his father 1905–47, his mother from 1911. His aunt Mary Ann Fee (d. 1956) acted as a second mother after his mother's death. His brother Patrick John (1921–83) was a medical doctor in Crossmaglen. After his father's illness in 1959 he made the residence of Patrick and his wife Deirdre (née Hall) his new home.
Educated at Cregganduff school (1928–36) and St Patrick's College, Armagh (1936–40), he gained a university scholarship to St Patrick's College, Maynooth (1940–44), where he graduated in Celtic studies (BA, 1st class hons). After a year's illness with pleurisy and pneumonia, he resumed studies in St Peter's College, Wexford (1945), and was ordained there for Armagh diocese (6 June 1948) by James Staunton (1889–1963), bishop of Ferns. He served briefly as assistant priest in Clonfeacle. In 1947–50 he studied early and medieval Irish history at UCD, graduating MA (1st class hons) with his thesis ‘The kingdom of Airghialla and its sub-kingdoms before 1100’. In 1950–52 at the Catholic University of Louvain he gained a Lic.Sc.Hist. with his thesis ‘The church of Armagh under lay control’ (published in Seanchas Ard Mhacha, v, no. 1 (1969)). His Louvain sojourn gave him a taste for travel, a European outlook, and an interest in Irish links with mainland Europe, leading to television programmes in the ‘Radharc’ series, historical trips, articles, lectures, and his books Gaelscrínte i gcéin (1960), Irish cultural influence in Europe (1966), Gaelscrínte san Eoraip (1986), and Columbanus in his own words (1974). He was conversant in French and German.
Assistant priest in Clonfeacle 1952–3, he became lecturer in modern history at St Patrick's College, Maynooth (NUI), 1953–9, and professor 1959–74. He served the college as registrar (1968–70), vice-president (1970–74) and president (1974–7). Elected to the NUI senate in 1964, he served on it until 1972, also serving (1972–4) as a member of the Higher Education Authority.
Ó Fiaich was fluent in Irish from an early age; as a youth he regularly attended the Irish summer school in Rannafast, Co. Donegal. His love of Irish was manifested later in his lectures on Gaelic topics and visits to the Gaeltacht. Active in Cumann na Sagart, the association of Irish-speaking priests, he was joint editor (1958–63) of its magazine An Sagart and director (1961–70) of ‘Glór na nGael’, its competition for areas with best Irish-language promotion. He was chairman of the government commission on the restoration of the Irish language (1959–63) and of Comhairle na Gaeilge, its advisory council (1965–8); author of Má Nuad (1972), a short history and guide of his beloved college; and a member of the committee for liturgical translations. He loved the Gaelic Oriel poetry of his native district, and edited for Éigse Oirialla Art Mac Cumhaigh: dánta (1973) and Art Mac Bionaid: dánta (with Liam Ó Caithnia, 1979). A selection of his essays in Irish on Irish literature and history was edited by Diarmaid Ó Doibhlin as Ón Chreagán go Ceann Dubhrann (1992).
Influenced by Fr Lorcán Ó Muirí (1883–1941), doyen historian of the Armagh diocese, Ó Fiaich helped to found (1953) Cumann Seanchais Ard Mhacha, the Armagh Diocesan Historical Society, and was editor (1954–77) of its journal Seanchas Ard Mhacha. His historical writings included Imeacht na nIarlaí (with Pádraig de Barra, 1972), Oliver Plunkett, Ireland's new saint (1975), and Oilibhéar Pluincéid (1976), as well as many articles in Seanchas Ard Mhacha and other journals. An essay in English by Seosamh Ó Dufaigh, ‘Tomás Ó Fiaich, scoláire’ (Seanchas Ard Mhacha, ix, no. 1 (1978), 3–34), lists his writings 1944–77.
Ó Fiaich was appointed archbishop of Armagh 22 August 1977, and was ordained bishop in St Patrick's cathedral, Armagh (2 October 1977), by the papal nuncio, Archbishop Gaetano Alibrandi (d. 2003), assisted by Bishops William Joseph Philbin (qv) and Francis Lenny (1928–78). He chose as his motto Fratres in unum (brothers at one), indicating his ecumenical leaning towards reconciliation and dialogue in a time of political turbulence. While he personally aspired to a united Ireland, he issued strong statements condemning violence by the IRA, loyalist paramilitaries, and the security forces alike. In a statement on 1 August 1978 after spending the previous Sunday visiting Long Kesh prison (the Maze), he compared conditions there to the slums of Calcutta. Created cardinal on 30 June 1979, he regarded the visit of Pope John Paul II to Ireland (29 September–1 October 1979) as the highlight of his episcopate. The pope visited Drogheda on 29 September and made a special plea for an end to violence. The cardinal tried to find a conciliatory solution to the hunger-strike in the Maze in 1981.
Ó Fiaich directed the renovation (1981–2) of St Patrick's cathedral, Armagh, and initiated a diocesan mission to Lagos, Nigeria, in 1982. He was beloved by his priests for his compassion and gentleness, and the warmth of his personality earned him the popular title ‘Man of the people’. He liked Irish traditional music and was an enthusiastic follower of Gaelic football. He died 8 May 1990 in Toulouse, France, after a heart attack while on pilgrimage to Lourdes. There were country-wide tributes to him and great crowds attended his lying-in-state in Armagh cathedral. After funeral mass (15 May 1990) he was buried in the cathedral grounds. A portrait by Thomas Ryan, RHA, is in the Cardinal Tomás Ó Fiaich Memorial Library and Archive, Armagh, which specialises in his interests: the Irish language, ecclesiastical history, the Irish diaspora, and sport.