Dictionary of National Biography, 1885-1900/O'Brien, Domhnall
O'BRIEN, DOMHNALL (d. 1194), king of Munster, son of Turlogh O'Brien (1009–1086) [q. v.], first appears in the chronicles in 1163, when he slew Maelruanaidh O'Cearbhaill, a chief whose territory was in the present county of Tipperary. He became king of Munster in 1168. He put out the eyes of his kinsman Brian O'Brien of Slieve Bloom in 1169, and made war on Roderic O'Connor [q. v.] In 1174 he met the Normans in battle at Thurles, co. Tipperary, and defeated them, and in 1175 strengthened his power at home by putting out the eyes of Dermot O'Brien and of Mathghamhain O'Brien at Caislen Ui Chonaing, now Castle Connell, co. Limerick, but was nevertheless driven out of Thomond by Roderic O'Connor in the same year. In 1176 he drove the English out of Limerick, and in 1185, when John was in Ireland, again defeated them, when they made an expedition from Ardfinnan on the Suir to plunder Thomond. In 1188 he aided the Connaughtmen under Conchobhar Moenmhoighe O'Connor in the defeat of John de Courcy in the Curlew mountains. In 1193 the English invaded Clare, and he in return ravaged their possessions in Ossory. Though often fighting against the English, he submitted to Henry II at Cashel in 1171, and part of his territory was granted during his life to Philip de Braose. He died in 1194; and the chroniclers, who elsewhere only describe his wars, blindings, and plunderings, commemorate him as ‘a beaming lamp in peace and war, and the brilliant star of the hospitality and valour of the Munstermen.’ His son Donogh Cairbrech [q. v.] is separately noticed.
[Annala Rioghachta Eireann, ed. O'Donovan, vols. ii. and iii. Dublin, 1851; Annals of Ulster, ed. MacCarthy, vol. ii., Annals of Loch Cé, ed. Hennessy, vol. i., Giraldus Cambrensis, vol. v. (all in the Rolls Ser.).]