O'Riordan, Michael (1857–1919), rector of the Irish College, Rome, was born in Kilmurray, Co. Limerick, son of John O'Riordan, a wealthy local farmer. Educated at the local national school and at the diocesan seminary in Limerick, he proved intellectually gifted and subsequently studied for the priesthood in Rome at the Irish College, the Propaganda College, and the Gregorian University. He took a great personal interest in the city and its Christian heritage, the inspiration for much of his future literary and religious career. Ordained in 1883, he worked until 1887 in the diocese of Westminster before returning home as curate of St Michael's parish, Limerick. He strongly supported both the Irish language revival and the temperance movement advocated by his friend and bishop, Dr Edward O'Dwyer (qv), who also founded St Munchin's College.
O'Riordan taught on the academic staff of St Munchin's, where his enthusiasm for Roman antiquity was such that students recalled exploiting it to divert him from work in progress. He acquired distinctions as easily as the popular approval he earned for his trenchant religious opinions. Michael O'Riordan, D.Ph., DD, DCL, became widely known through his prominent role in the Catholic Literary Institute and his published articles in various journals, notably the Irish Ecclesiastical Record and the Leader. Some of what he wrote was unadorned polemic: to Sir Horace Plunkett (qv), whose Ireland in the new century (1904) was an imperious broadside at peasant, priest, and politician, O'Riordan gave a lengthy, hostile response in Catholicity and progress in Ireland (1905) which reflected the anger of the hierarchy and of nationalists in general. It set the tone for his appointment, also in 1905, as rector of the Irish College in Rome.
O'Riordan, like his predecessors, found it necessary to maintain a high Irish profile at the Vatican. He was effectively the Irish hierarchy's ambassador in Rome, its most potent representative abroad. In 1907 Pope Pius X made him protonotary apostolic. His vice-rector was John Hagan (qv), another graduate of the Irish College who shared his intense nationalism. O'Riordan fell short of Hagan's preference for physical-force revolution (nor had he great confidence in the achievement of Irish home rule while it relied on the Liberal party in Britain for support) but their common objective was Irish independence with a catholic power structure closely allied to Rome. As the first world war erupted in 1914, the Irish hierarchy under Cardinal Michael Logue (qv) opposed the war, Irish participation, and the threat of conscription. O'Riordan's Limerick mentor, O'Dwyer, was among the most vehement, as individual churchmen vacillated in degrees of condemnation. O'Riordan abhorred the advocacy of the war by the Irish party leader John Redmond (qv), but was more troubled that the party's demise would scuttle home rule in Ireland as protestant unionists prepared to resist its postwar implementation. He also understood that the Irish party remained the hierarchy's only political influence in London. His annual holidays, spent in Ireland until the outbreak of the war, afforded him direct contact with religious and political developments at home and the opportunity to deliver papers at the Maynooth Union.
Both O'Riordan (who cultivated especially cordial relations with Pope Benedict XV, elected 1914) and Hagan exploited the turmoil of the times to win Vatican sympathy for nationalist Ireland in spite of British diplomatic pressure. O'Riordan facilitated Bishop O'Dwyer's access to the pope on the Irish hierarchy's behalf, the bishop in turn promoting papal peace initiatives in 1915. In the same year O'Riordan received the papal honour of consultor to the Consistorial Congregation. Hagan, meanwhile, developed closer ties with militant Sinn Féin and the Irish Volunteers. The Easter rising of 1916 and its aftermath overwhelmed the fragile Irish party, which was fatally weakened by Redmond's death in 1918 amid an emotional wave of anti-conscription feeling in Ireland. O'Riordan, no supporter of the rising, yet sympathetic to the rebels' aims, was in failing health and unable to offset Hagan's vigorous advocacy of Sinn Féin, especially after its general election victory in December 1918. Already in May 1919 Sinn Féin's Seán T. O'Kelly (qv) was taking up position as envoy in Rome with Hagan's full support.
O'Riordan, living long enough to witness the beatification (May 1919) of the seventeenth-century Irish martyr Oliver Plunkett (qv), raced against time to complete a monumental series of articles entitled ‘Life of the venerable Oliver Plunkett’ for the Catholic Bulletin, a journal in which Irish College personnel provided frequent and highly political material against British and unionist interests. Appearing posthumously in eight parts between October 1919 and August 1920, the unfinished assignment was a remarkable memorial for any man on the verge of death.
His many other essays included titles such as A criticism of Draper's history of the conflict of religion and science; Life of Columbanus, and other Irish saints in Italy; and A reply to Dr Starkie's attack on the managers of Irish national schools. He also wrote articles for the Catholic encyclopedia and with his knowledge of church history was postulator in the cause of Irish martyrs. After his death in Rome, 27 August 1919 (reported the same day in the Limerick Leader), he was succeeded as rector by John Hagan, not without fears among many Irish and Vatican churchmen that this heralded a shift to extremism.