O'Neill, Henry (1798–1880), artist and antiquarian, was born in Dundalk, Co. Louth, or possibly in Clonmel, Co. Tipperary, the only child of Henry O'Neill; his mother is said to have been a daughter of a prominent bookseller and publisher, Samuel Watson (qv). Both parents died while he was young and he was looked after by his father's sister, Sarah O'Neill, a haberdasher in South Great George's St., Dublin, who provided him with a good education. His artistic talent was noted, and Henry was sent in 1815 to the Dublin Society's schools, where he excelled, carrying off the first premiums in every class in which he competed. The Society recognised his ability by presenting him with a silver medal ‘as a reward for his industry and talents’. While he was studying art, Henry helped his aunt by designing patterns for lace and for embroidered shawls, and spent some time teaching drawing. After he fell out with his aunt, his mother's family assisted him financially, and he appears to have spent some time around 1841 working in the library of TCD.
He began to exhibit his work, mostly watercolours, at the Royal Hibernian Academy in 1835 and continued to do so until 1879. He was elected an associate of the Academy (1837) but resigned in 1844 when he took offence at not being accepted as a full member the previous year. He painted some portraits, including one of the famous Dublin beggar ‘Zozimus’ (Michael Moran (qv)), and one of Bartholomew Lloyd (qv). O'Neill had several of his landscape drawings published alongside those of Andrew Nicholl (qv) and the antiquary George Petrie (qv) in Picturesque sketches of some of the finest landscapes and coast scenery of Ireland (1835); the same year the antiquarian artist W. F. Wakeman (qv) adapted O'Neill's drawings for his Fourteen views in the county of Wicklow. O'Neill was, however, not particularly successful as an artist and left for London in 1847; still unsuccessful, he decided to enlist in the army, was bought out by some friends, and returned to Dublin.
O'Neill is remembered especially for his Illustrations of the most interesting of the sculptured crosses of ancient Ireland (1857), a well-illustrated account of several of the decorated Irish high crosses. O'Neill used these monuments as evidence for a sophisticated and distinctively Irish civilisation in ancient times. Other antiquarian works include The fine arts and civilization of ancient Ireland (1863) and several papers published in early volumes of the RSAI Journal. These show him to have been an intelligent man, working generally in the spirit of that new scientific and empirical antiquarianism usually associated with the names of George Petrie and John O'Donovan (qv). In spite of this, however, O'Neill strongly disagreed with some of the conclusions reached by Petrie, preferring the more esoteric study by Henry O'Brien (qv) of the Irish round towers to Petrie's prize-winning essay. He himself published one volume (1877) on round towers, in which he espoused the theory of their pagan origin.
O'Neill's work, especially that on high crosses, shows signs of the influence of the developing Celtic revival movement. His patriotism was not confined to his antiquarian work: he was a member of the Repeal Association founded by Daniel O'Connell (qv), and made a painting of O'Connell and his fellow prisoners in Richmond gaol in 1843. He later produced a series of lithograph portraits of the Young Irelanders; in 1868 he published an anti-landlord pamphlet entitled Ireland for the Irish, which appeared in at least two editions. It is possible that his political views adversely affected sales of his work, and he was noted for being rather argumentative in his dealings with other scholars and learned bodies. However, in April 1878, when O'Neill was in his eightieth year, seriously ill and in poverty in Dublin, a committee of titled and respectable art patrons was formed to help him and his wife and family. The committee included Lord Talbot de Malahide (qv) a prominent antiquarian, and Sir Arthur Guinness (qv), a tory, as well as Sir Robert Kane (qv), a catholic scientist and educationist.
At the time of his death in 109 Lower Gardiner St., Dublin, on 21 December 1880, he was survived by his widow, Juliet (née Thierry), who was probably his second wife, and by a daughter and three sons, some of whom presently moved back to London. One of the sons had been given the name Tyrone, perhaps suggesting that O'Neill's political views had been influenced by his awareness of the lost glories of his ancestors.