convivial than provident. The son was educated at the endowed school of New Ross, and entered Trinity College, Dublin, as a pensioner in November 1810. A portion of the cost of his education was defrayed by the borough of New Ross; in September 1826 he refunded the amount—116l.—and was voted the freedom of the borough and a gold box. O'Brien obtained a scholarship at Trinity College in 1813, graduated B.A., and took the gold medal in 1815. He was especially distinguished in mathematics, in 1820 obtained a fellowship, and taking holy orders, was created D.D. in 1830. He was one of the six Dublin University preachers from 1828 till 1842, and became Archbishop King's lecturer in 1833, when the divinity school in the university was thoroughly reorganised.
O'Brien maintained through life strongly evangelical views. He was well read in the works of the reformers and their opponents, and in those of Bishop Butler and the Deists. In 1829 and 1830 his university sermons on the reformation doctrine of justification by faith became, when published in 1833, a standard work. As Archbishop King's lecturer, he lectured on ‘The Evidences of Religion, with a special reference to Sceptical and Infidel Attempts to invalidate them, and the Socinian Controversy.’ Resigning his fellowship in 1836, he became vicar of Clonderhorka, Raphoe, but removed in 1837 to the vicarage of Arboe, Armagh, which he held till 1841. On 9 Nov. 1841 he was nominated dean of Cork, and instituted on 5 Jan. 1842. On 9 March in the same year he was raised by the prime minister, Sir Robert Peel, to the bishopric of the united dioceses of Ossory, Ferns, and Leighlin.
O'Brien was a daily worshipper in his cathedral, but he seldom preached or spoke except at the meetings of the church education society, of which he was an active champion. Naturally opposed to the Oxford movement, he did what he could to stem its advance in sermons and writings between 1840 and 1850. In 1850 appeared his ‘Tractarianism: its present State, and the only Safeguard against it.’ To the disestablishment of the Irish church O'Brien opposed a well-sustained resistance, and Archbishop Trench acknowledged much aid from his advice in the course of the struggle. When disestablishment came, O'Brien helped to reorganise the church, and moderated the zeal of his evangelical friends in their efforts to revise the prayer-book in accordance with their own predilections. O'Brien died at 49 Thurloe Square, London, 12 Dec. 1874, and was buried in the churchyard of St. Canice's Cathedral, Kilkenny. On 19 Dec. Archbishop Trench described him, when addressing the clergy of the diocese assembled to elect a successor in the see, as a fit representative of the ideal ἀνὴρ τετράγωνος, i.e. the philosopher's four-square man, able to resist attack from whatever quarter made. His personal appearance was dignified and imposing.
He married in 1836 Ellen, second daughter of Edward Pennefather, lord chief justice of Ireland, by whom he had eight sons and five daughters.
O'Brien's chief work, ‘An Attempt to explain the Doctrine of Justification by Faith only, in Ten Sermons,’ 1833, was long popular; 2nd ed. 1862, 3rd ed. 1863, 4th ed. 1877, and 5th ed. 1886. His primary and second charges, 1842 and 1845, published in London, and directed in great part against Tractarianism, each went to two or three editions, and the substance of the second was again reproduced in 1847. In 1833 he attacked Edward Irving's views in ‘Two Sermons on the Human Nature of our Blessed Lord,’ which were re-published in 1873 with a ‘Plea from the Bible and the Bible alone for the Doctrine of Baptismal Regeneration.’
Others of his works were: 1. ‘Sermons upon the Nature and Effects of Faith,’ 1833; 5th ed. 1891. 2. ‘The Expediency of restoring at this Time to the Church her Synodical Powers considered,’ 1843. 3. ‘The Church in Ireland: our Duty in regard to its Defence,’ 1866. 4. ‘The Case of the Established Church in Ireland,’ with app., 1867–8; 3rd ed. 1868. 5. ‘The Disestablishment and Disendowment of the Irish Branch of the United Church considered,’ 1869; three editions.
[Private information; Carroll's Memoir of J. T. O'Brien, D.D., 1875, with portrait, somewhat hostile; Newman's Justification, 1838, pref.; Illustr. London News, 1875, lxvi. 23; Men of the Time, 1872, p. 727; Webb's Compendium of Irish Biography, 1878, p. 371; Cotton's Fasti, 1847, i. 199, ii. 290–1.]
O'BRIEN, JOHN (d. 1767), Irish catholic prelate, was vicar-general of the united dioceses of Cork, Cloyne, and Ross. In audience of 10 Dec. 1747 Pope Benedict XIV approved the separation of Cork and Cloyne, which had been held in union since 1429, and the appointment of O'Brien to the bishopric of Cloyne and Ross. His brief was dated 10 Jan. 1747–8. He died, according to Brady, in 1767, when he was succeeded in his see by Matthew MacKenna (Episcopal Succession, ii. 99). Martin states, however, that O'Brien was bishop of Cloyne and Ross from 1748 to 1775.
To him is generally attributed, though on