Dictionary of National Biography, 1885-1900/O'Neill, Henry (d.1392)
O'NEILL, HENRY (d. 1392), Irish chief, called by Irish writers Enrí aimhreidh or the Contentious, was son of Niall mór O'Neill, chief of the Cinel Eoghain, son of Aedh reamhar or the Fat, also chief, who died in 1364, and was descended from Brian O'Neill, who was slain at the battle of Down in 1260, and was twelfth in descent from Muircheartach (d. 943) [q. v.], son of Niall (870?-919) [q. v.] These points of descent explain several references to him in poetry. Some verses by Brian ruadh Mac Conmidhe [q. v.] in the poem 'Temair gach baile i mbi ri' ('Any demesne whatever in which there is a king may justly be held to be Tara'), addressed to Henry O'Neill (d. 1489) [q. v.], great-nephew of Enrí aimhreidh, suggest that the Irish Enrí is not Henricus, but énri, sole king. Enrí aimhreidh is the earliest O'Neill of the name. The 'Annals of Loch Cé' state that he was called the Contentious by antiphrasis because he was so peace-loving. His descendants were among the most turbulent of the Ulstermen. He lived at Ardsratha, now called Ardstraw, co. Tyrone, not far from Strabane, where a gateway, flanked by towers and other fragments of his castle, is still to be seen, at the foot of Slieve Truim, a mountain often marked on maps as Bessy Bell. He never became chief of Cinel Eoghain, as he died in 1392, before his elder brother, Niall óg, whose son, Owen Eoghan, is noticed separately. Enrí married his cousin Aiffric, daughter of Aedh O'Neill. She died in 1389, having borne him six sons: Domhnall, Brian, Niall, Huaidhri, Seaan, and Enrí. The six sons, their followers, and descendants formed a sept known as Clann Enrí, and afterwards as Sliocht Enrí aimhreidh, most of whose lands at the plantation of Ulster became the property of the Earl of Abercorn. Domhnall was taken by the English in 1399, and sent a prisoner to England, but was ransomed in 1401, and in 1403 became chief of Cinel Eoghain. He was slain at Keenaght, Co. Derry, by Domhnall and Aibhne O'Cahan in 1432. Brian made an expedition into Donegal in 1401. He was met by the Cinel Conaill under Toirdhealbhach, son of Niall garbh O'Donnell, and hard pressed while driving off his spoil of cattle. At last he was surrounded, and after killing Enrí O'Gairmleaghaidh with one stroke of his sword, was himself killed by Toirdhealbhach O'Donnell.
[Annala Ricghachta Ui Eireann, ed. O'Donovan, vols. iii. and iv.; Bishop William Reeves's Acts of Archbishop Colton, Dublin, 1850; Annals of Loch Cé, ed. Hennessy, vol. ii. (Rolls Ser.); Fitzgerald's Statistical Account of Ardstraw; Lewis's Topographical Dict. of Ireland, vol. i.; Egerton MS. 111 (Brit. Mus.),fol. 38 b.]