Ancient Ireland, illustrated with chromo and other lithographs, and several woodcuts,' London, 1863. This ambitious work attempts to prove the existence of advanced civilisation in Ireland at a prehistoric period, and to refute the conclusions of Dr. George Petrie [q. v.] in his 'Ecclesiastical Architecture of Ireland' (1845). O'Neill maintained that the round towers were of pagan origin, but this view is now discredited ; nor have his other contentions borne the test of criticism as well as those which he attacked. He also wrote in 1808 a brochure claiming 'Ireland for the Irish 'and attacking 'landlordism.' His last production was a lithograph, with a careful description of the twelfth-century metal cross known as the 'Cross of Cong.' O'Neill died at 109 Lower Gardiner Street, Dublin, on 21 Dec. 1880, in the same year as his namesake the artist, Henry Nelson O'Neil [q. v.], leaving a family in straitened circumstances.
[Irish Times, 24 Dec. 1880; Athenæum, 1881, i. 27 (where, and also in the Academy. O'Neill is wrongly credited with a separate work on the Round Towers); Brit. Mus. Cat.]
O'NEILL, HUGH (d. 1230), lord of Cinel Eoghain, often called less accurately lord of Tyrone, was perhaps a son of the Aedh or Hugh O'Neill whom the 'Annals of Ulster' relate to have been slain in 1177. The younger Hugh O'Neill seems to have become chief of the Cinel Eoghain about 1197. In 1199, while John de Courci was plundering in Tyrone, Hugh went to some place near Larne, and was in the act of burning the town when the English took him by surprise. Hugh, however, defeated the English, and so forced De Courci to come back from Tyrone. Later in the same year O'Neill was engaged in warfare with the Cinel Connell and O'Heignigh the chief of Fermanagh, but in the end some sort of peace was made. In 1201 Hugh and O'Heignigh went to help Cathal O'Connor (1160?-1224) [q. v.] in Connaught against Cathal Carrach and William Burke [see under Fitzaldhelm, William]. They raided as far as Tebohine in co. Roscommon; but when Cathal Crobhderg wanted to proceed against Cathal Carrach and William Burke, the northern Irish refused, and turned homewards. Burke and Cathal Carrach pursued them, and overtook them near Ballysadare. At first the men of Connaught would not join battle, but eventually they defeated and slew O'Heignigh, and compelled Hugh to give hostages to Cathal Carrach. It was perhaps in consequence of this defeat that Hugh was deposed by the Cinel Eoghain in favour of a MacLochlainn. O'Neill, however, soon recovered his lordship; in 1207 Hugh de Lacy, earl of Ulster [q. v.], made a raid into Tyrone, but could exact no pledges from O'Neill. In 1209 Hugh O'Neill was plundering Inishowen, and had a great fight with the elder O'Donnel,but eventually the two made peace, and united against the English. In 1211 Hugh defeated the English at Narrow-Water in co. Down, and next year repulsed an invasion of Tyrone by John de Gray, and afterwards burnt the castle of Clones, which the justiciar had lately erected. In 1214 he defeated the English with great slaughter, and burnt Carlingford, and next year was again raiding in Ulster. In 1222 Hugh de Lacy returned to Ireland against the king^s consent, and, joining with Hugh O'Neill, destroyed the castle of Coleraine, and ravaged Meath and Leinster. O'Neill also supported De Lacy in his later warfare, which led to the despatch of William Marshal, second earl of Pembroke and Striguil [q. v.], to Ireland in 1224. In 1226 O'Neill went to the aid of the sons of Roderic O'Connor (1116-1198) [q. v.] against Hugh, son of Cathal O'Connor called Croibhdhearg [q.v.], and set up Turlough O'Connor, Roderic's third son, as prince of Connaught. O'Neill himself evaded the English, but Turlough was soon expelled and forced to take refuge in Tyrone, Hugh O'Neill died a natural death in 1230, though he was 'the person that it was least thought would find death otherwise than by the foreigners' (Annals of Ulster, ii. 285).
The Irish annalists speak of Hugh O'Neill with much exaggeration, as 'a king who had never rendered hostages, pledges, or tribute to English or Irish; who had gained victories over the English, and cut them off with great slaughter; who had never been expelled or exiled, and was the most hospitable and defensive that had come of the Irish for a long period' (Annals of Kilronan). The 'Annals of Loch Cé' call Hugh the 'most generous king and very best man that had come of the men of Erinn for a long time.' Hugh O'Neill is spoken of as 'worthy future arch-king of Ireland' (Annals of Ulter, ii. 285); and in a solitary reference to him in the English records, he is said to have styled himself king of all the Irish of Ireland (Calendar of Documents relating to Ireland, i. No. 1840). In the same place reference is made to his having been brought into the English king's peace.
[Annals of the Four Masters, ed. O'Donovan; Annals of Loch Cé (Rolls Ser.), and Annals of Ulster, ed. Hennessy (the dates are given in accordance with the Ulster Annals; the chronology of the Annals of the Four Masters is generally a year earlier); Webb's Irish Biography, pp. 405–6.]