O'Mahony, John (1815–77), founder of the Fenian Brotherhood and Gaelic scholar, was born probably on 12 January 1815 at Clonkilla, near Mitchelstown, Co. Cork, the son of Daniel O'Mahony, a catholic farmer and landowner; there is no record of his mother's name. Immensely proud of his family pedigree, he claimed descent from the chiefs of the O'Mahonys, large landowners whose property was seized by the earl of Kingston in O'Mahony's grandfather's time. The loss of the family's patrimony was bitterly resented by the O'Mahonys: John's father and uncle fought in the 1798 rising. He grew up at Loughananna, Kilbeheny parish, Co. Limerick, and was educated at the Hamblin classical school in Cork. A talented student, he enrolled at TCD in 1833 to study languages – Hebrew, Sanskrit, Latin, Greek, French, and Irish – but left before taking his degree. After his father's death in 1840, O'Mahony leased land in Kilbeheny, and may have moved to a farm in Mullach near Carrick-on-Suir, Co. Tipperary. On the death of an elder brother, he inherited the family property, and was locally regarded as the chief of the O'Mahony clan.
Insurrection and exile O'Mahony joined Daniel O'Connell's (qv) Repeal Association in 1843, but left when the Young Irelanders seceded in July 1846 over the issue of physical force. Coming under the influence of the militant writings of James Fintan Lalor (qv) and John Mitchel (qv), he described his views at this time as ‘ultra-democratic’, believing that the land of Ireland should be owned by the Irish people rather than by alien landlords. During the early months of 1848 he helped organise Confederate Clubs in south Tipperary and in July led a retinue of followers into Carrick-on-Suir to assist the attempt at insurrection, impressing Young Ireland leaders with his handsome appearance and manly bearing. After the failed engagement at Ballingarry, Co. Tipperary (29 July), O'Mahony evaded arrest with John Savage (qv), Philip Gray (qv), and others in the Suir valley, continuing to harass crown forces and mounting an attack on Portlaw police barracks. A reward of £100 was offered for his arrest. Recognising that the position was hopeless, O'Mahony abandoned an attempt to rescue the imprisoned leaders, dismissed his followers, and made over his property to his sister Jane (d. 1893), mother of the National League activist, John Mandeville (qv). He then took a boat from Dungarvan to South Wales and after six weeks made his way to Paris, where he joined other Irish exiles. Supporting himself by teaching, he shared frugal lodgings at 26 Rue Lacépede with James Stephens (qv), with whom he formed a close friendship. The two probably joined a radical secret society, and took to the streets to resist the Bonapartist coup of December 1851.
The Fenian Brotherhood In December 1853 O'Mahony emigrated to New York where he associated with John Mitchel (who became a lifelong friend) and other Irish nationalists. In February 1856 O'Mahony and his fellow Young Ireland exile Michael Doheny (qv) founded the Emmet Monument Association (EMA), which planned to raise an Irish-American force to invade Ireland while the British army was preoccupied with the Crimean war. The proposed invasion came to nothing, but it led to the establishment of an Irish-American revolutionary committee which in late 1857 sent instructions to Stephens to organise the republican movement in Ireland. Stephens founded the IRB in Dublin in March 1858, and in April 1859 O'Mahony established its American equivalent (based on the EMA). A keen student of ancient Irish history, he called it the Fenian Brotherhood – the name inspired by the mythical Celtic warriors of the Fianna – and he became its leader, or ‘head centre’. He regarded the Brotherhood more as an revolutionary army than a secret society and eschewed much of the secrecy employed by its Irish counterpart. He also eschewed the IRB oath, primarily to avoid offending the catholic clergy and, although a robust defender of the Brotherhood from clerical denunciation, was generally less anti-clerical than Irish colleagues. While O'Mahony saw the Fenian Brotherhood as an equal partner, Stephens considered it a subsidiary body whose role was to provide money and arms for the IRB, and this disagreement was never satisfactorily resolved. Stephens inundated O'Mahony with bitter complaints about the poor level of American support, and in December 1860 they met in Dublin to resolve their differences. Stephens subjected O'Mahony to a humiliating harangue, but eventually they worked out a plan whereby American aid was to assist an Irish uprising. Although O'Mahony often found Stephens's demands unreasonable and relations between them were usually strained, the two men maintained their regard for each other: O'Mahony often defended Stephens from his detractors, and Stephens regarded O'Mahony as ‘far and away the first patriot of the Irish race’ (Ryan, Fenian chief, 45). While in Ireland O'Mahony met various IRB leaders and inspected the organisation in Dublin, Kilkenny, Tipperary, and Cork, before returning to New York in March 1861; it was his last visit to Ireland.
The American civil war started shortly after O'Mahony's return to New York and led him to postpone plans for insurrection in Ireland. He enlisted in the union army and was appointed colonel of the New York 99th regiment, largely recruited from the ranks of the Fenian Brotherhood. He had a quiet war, serving only 100 days on active duty from 2 August to 9 November 1864 when his regiment was assigned to guard prisoners at Elmira, New York. During the war, membership of the Fenian Brotherhood expanded rapidly, growing far beyond its New York heartland and reaching an estimated 250,000 by 1865. In November 1863 O'Mahony convened the first convention of the Fenian Brotherhood in Chicago which asserted the organisation's independence of Stephens and its equal status with the IRB. However some members criticised the Brotherhood's inactivity, and these criticisms were repeated at a second convention in Cincinnati in January 1865. When the war ended in April 1865, O'Mahony began to plan for revolution in Ireland, launched the sale of Irish republic bonds, and sent several veteran Irish-American army officers to Ireland to prepare the IRB for action. Critics, however, claimed that his leadership lacked vigour and accountability, and at the Brotherhood's third convention in October 1865 in Philadelphia, it reorganised itself under a powerful senate, from which O'Mahony was excluded. He was made president, but shorn of effective powers. There were also differences over strategy: O'Mahony believed all efforts should be directed towards an uprising in Ireland while his opponents argued for an invasion of Canada. Amid much rancour the Brotherhood split in December 1865, with the president of the senate, William Randall Roberts (qv), leading the majority ‘senate’ wing, and O'Mahony leading a rump ‘official’ wing which remained affiliated to the IRB. To support his position, in January 1866 in New York O'Mahony founded the Irish People newspaper, which regularly denounced the Roberts faction as men of no talents, education, or social position. In an ill-advised attempt to reassert his leadership and assuage those desperate for action, O'Mahony mounted an attempted invasion of Campo Bello Island, New Brunswick, on 19 April 1866; the operation was bungled and easily thwarted by combined American and British naval forces. The plan was probably betrayed by ‘Red Jim’ McDermott (qv), who was widely suspected of being a spy, but remained a trusted lieutenant of O'Mahony. Critics of O'Mahony maintained he was a poor judge of character who surrounded himself with fools and flatterers, and that his combination of naivety and mysticism made him particularly ill-suited to lead a revolutionary organisation.
The Campo Bello fiasco cost O'Mahony much credibility, and he resigned as president of the Brotherhood on 11 May 1866 being replaced by Stephens. Later reinstated as president, O'Mahony continued to support insurrection in Ireland and on hearing of the outbreak of March 1867 dispatched a brig, the Erin's Hope, with forty men and thousands of rifles from New York on 12 April. It arrived in Sligo Bay on 20 May, ten weeks after the rising had fizzled out, and most of those aboard were soon arrested. O'Mahony was replaced as president by John Savage (qv) on 22 August 1867. He again became president after Savage's retirement in August 1872, but by then the Brotherhood's membership had drastically fallen and its influence was largely confined to New York. The Roberts wing also declined and by the mid 1870s both bodies had been eclipsed by Clan na Gael.
Cultural nationalism O'Mahony devoted himself to cultural as well as political nationalism, particularly during periodic bouts of disillusionment with Stephens and Irish-American factiousness. An accomplished Gaelic scholar, he and Doheny wrote the ‘Gaelic Department’ column in the Irish-American until September 1871. O'Mahony's most ambitious scholarly work was his translation of Geoffrey Keating's (qv) Foras Feasa ar Éirinn, which he completed on 18 July 1857, and published as The history of Ireland, by Geoffrey Keating, D.D., translated from the original Gaelic, and copiously annotated (New York, 1857). It was an immense task, which apparently brought on mental collapse, causing O'Mahony to spend some months in an asylum. Although better than previous translations, it was based on a flawed original text, and was found deficient by later scholars; O'Mahony himself believed it had been rushed and was unhappy with it. He received little reward for his labour. The English publishers Hodges and Smith claimed that he had reproduced notes from John O'Donovan's (qv) translation of the Annals of the Four Masters without attribution, and got an injunction prohibiting its sale in the UK.
Last years, death, and funeral O'Mahony's Irish People folded in 1870 and afterwards he eked out a precarious living by writing for the Celt and other Irish journals. The bitter split in the Fenian Brotherhood festered and continued to earn him abuse, including accusations of indecisive leadership and financial malfeasance. Whatever truth there may have been in the former, there was none in the latter, and he answered his critics in a letter written on 2 April 1873 (reprinted in the Irish World of 17 March 1877), claiming that with the $500,000 it had collected the Fenian movement had ‘swept away the bloodstained Anglican church establishment from the Irish soil and had driven the first nail into the coffin of Irish landlordism’.
In July 1873 O'Mahony founded a new Fenian paper, the American Gael, but it soon failed. His health declined in 1874 and he lived his final years in dire poverty, aggravated by pride, generosity, and weakness for a hard-luck story. John Boyle O'Reilly (qv) recalled his haggard appearance during those years: ‘A tall gaunt figure – the mere framework of a mighty man; a large, lustreless face, with deep-sunken introverted eyes . . . an overcoat always buttoned, as if to hide the ravages of wear and tear on the inner garments; something of this, and something too of gentleness and knightlihood, not easily described, were in the awkward and slow moving figure, with melancholy and abstracted gaze’ (Maher, 21–3). He remained nominal president of the Fenian Brotherhood until serious illness forced his resignation on 28 January 1877. By chance, his friends Thomas Clarke Luby (qv) and Dr Denis Dowling Mulcahy (qv) found him dying in a New York tenement, and cared for him in his last days. O'Mahony died 6 February 1877 in New York; he never married.
Clan na Gael organised the funeral, which rivalled that of T. B. McManus (qv) as a memorable nationalist demonstration. The body was transported to Dublin but Archbishop Paul Cullen (qv) refused admission to the pro-cathedral and it lay in state at the Mechanics’ Institute in Lower Abbey Street. On Sunday, 4 March, a great public funeral to Glasnevin cemetery drew representatives from all shades of nationalism. Police estimated that about 4,000 people took part in the procession and another 70,000 watched sympathetically. No graveside oration was permitted, so Charles Kickham (qv), a kinsman on O'Mahony's mother's side, spoke outside the cemetery gates, praising O'Mahony as a selfless patriot who had devoted his life to Ireland. Widely admired for his integrity and idealism, O'Mahony inspired numerous poetic tributes, notably by Douglas Hyde (qv), Charles Graham Halpin (qv), and O'Mahony's friend and secretary Michael Cavanagh (qv).
A portrait of O'Mahony in uniform was painted in New York by an unknown artist in 1868; it was later presented to the Dublin Municipal Gallery by Alice, Lady Esmonde. O'Mahony's Gaelic manuscripts are in the Presbyterian Private Library in Philadelphia; other papers are held in the Catholic University of America (Washington DC) and the NLI.