to the young pretender, then preparing for the invasion of England. He landed with him at Lochnanuagh on 5 Aug. 1745, and through the whole campaign he remained his chief adviser in both civil and military matters. O'Sullivan commanded with Cameron of Lochiel the nine hundred highlanders who captured Edinburgh on 16 Sept. 1745 (Lockhart, Memoirs, ii. 488). He was present at Prestonpans, and, in his capacity as adjutant and quartermaster-general, drew up the rebel army in line of battle at Culloden. O'Sullivan escaped back to France on 1 Oct. 1746. In 1747 he was knighted by the pretender for his services. The date of his death is unknown. He married a Miss FitzGerald, and left a son.
Thomas Herbert O'Sullivan (d. 1824), son of the above, who entered the Irish brigade, was appointed to accompany the privateer Paul Jones in his expedition against the Irish coast in 1779. O'Sullivan quarrelled with his fellow-commander and fled to America, where he entered the British army under Sir Henry Clinton at New York. He left the British army, probably at the end of the American war of independence, 1783, and entered the service of Holland. He died a major in the Dutch service at the Hague in 1824. His son, John O'Sullivan, employed in the American consular service, died in 1825.
[O'Callaghan's Irish Brigades; Webb's Compendium of Irish Biography.]
O'SULLIVAN, MORTIMER (1791?–1859), Irish protestant divine, second son of a schoolmaster of Clonmel, co. Tipperary, was born there in 1791 or 1792. He was educated with his elder brother Samuel (see below) and his friend Dr. William Phelan [q.v.] at the Clonmel endowed school. The headmaster, Dr. Richard Carey, an intimate friend of the elder O'Sullivan, was an earnest protestant, while the O'Sullivans were catholics. Carey was much revered by his pupils, and the remark of a priest — that Carey could not be saved — first led Mortimer to 'reason himself into the belief of the right of private judgment, and out of the church of Rome.' He entered as a protestant scholar at Trinity College, Dublin, in 1813, and proceeded B.A. in 1816, M.A. 1832.
After six or seven years at the university O'Sullivan returned to the south, and became second master of the Tipperary endowed school, and curate of the parish of Tipperary. He was the first master of the Royal School at Dungannon, near Killyman, and was also in Waterford for a time. He was chaplain of St. Stephen's chapel, Dublin, and on Dec. 1827 was collated to the prebend of St. Audoen's in St. Patrick's Cathedal, Dublin. This office he resigned on 24 Aug. 1830 on being presented to the rectory of Killyman, co. Armagh, at the death of William Phelan (15 June).
At a very early age O'Sullivan became interested in the relations between the catholic and protestant churches in Ireland. In 1824, in reply to Thomas Moore's 'Captain Rock,' he wrote 'Captain Rock Detected, or the Origin and Character of the Recent Disturbances, and the Causes, both moral and political, of the present alarming condition of the South and West of Ireland, fully and fairly considered and exposed, by a Munster Farmer,' London, 1824. Here O'Sullivan boldly attacked the landlords and the land system, while defending the Irish church and clergy (cf. Blackwood's Mag. July 1824, p. 97).
O'Sullivan gave evidence before the select committee of lords and commons on the state of Ireland, 26 April and 27 May 1825. The results were published by himself and Dr. Phelan in 'A Digest of Evidence on the State of Ireland in 1824–5,' &c., 2 vols. London, 1826. Ten years later, on 26 May 1835, when summoned to give evidence before the select committee on orange lodges, O'Sullivan stated that the orange societies were of importance in preserving the peace of Ulster. In the same year O'Sullivan was sent with the Rev. Charles Boyton as a deputation to England and Scotland from the Irish clergy to make known the condition of their church. O'Sullivan described with native eloquence and passion the insecurity of the Irish protestant clergy and the injustice of the tithe system in Exeter Hall, London, on 20 June and 11 July 1835, and in many provincial towns. On his return to Ireland in October 1835 he engaged in a controversy with Dr. Daniel Murray [q. v.], the catholic archbishop of Dublin, who charged him with misreporting his words before the lords' committee on the circulation of the bible among the laity. The correspondence was published. In September 1836 O'Sullivan was again in Glasgow, and on 27 May 1837 a fifth enthusiastic meeting was held in Exeter Hall. Full reports of all, with correspondence, were published by O'Sullivan and the Rev. Robert McGhee in 'Romanism as it rules in Ireland,' &c., 2 vols. London and Dublin, 1840. In 1851 O'Sullivan was Donellan lecturer at Trinity College, and in 1853 he was made rector of Tanderagee, near Ballymore. During the latter years of his life he resided in Lower Gloucester Street, Dublin, and officiated as chaplain to the Earl of Carlisle, the lord-