Domnall ua Néill [Domnall of Armagh] (d. 980), high-king of Ireland, was the son of , better known as Muirchertach of the Leather Cloaks, king of Ailech, and Gormflaith, daughter of Cuilennán mac Máele Brigte. He was a dynast of Cenél nÉogain and among the early Irish lords was unusual in his use of naval power to accomplish military objectives. As part of his campaigns he moved his ships overland, from one navigable water to another, in order to make rapid attacks.
Domnall became king of Ailech on the death of his father in 943 and first appears in the chronicles in 945, when he and his brother Flaithbertach attacked a viking camp at Lough Neagh and destroyed their fleet. When Flaithbertach was slain in 949 the death was a blow to Domnall and for some years he is not mentioned in the chronicles. In 954, he led an army into Brega in a challenge to the high-king Congalach mac Máele Mithig. The next year, 955, Domnall conducted the first of his interesting naval manoeuvres when he removed his ships from Lough Neagh, and had them transported first across Airgialla to Lough Erne, and then to Connacht, to Lough Oughter, in order to devastate Bréifne and take hostages. This display of military prowess was happily timed, and when Congalach was slain the following year, Domnall ascended to the high-kingship. In 960 he raided the eastern kingdom of Dál nAraidi to secure their recognition of his lordship. A demonstration of power was made by Domnall in 963 when he transported his fleet from the northern Blackwater across Sliab Fuait, in the Fews, to Lough Ennell. Two years later, during the great famine of 965, he invaded Connacht again and took the hostages of the provincial king Fergal mac Airt.
By 968 Domnall was ready to move south, and in that year he led a campaign of two months' duration against the vikings and the men of Leinster, raiding from the River Barrow to the sea. This began the hostilities between Domnall and the famous lord of Dublin named Olaf Cuarán (Sihtricson) that would continue for a decade. In 970 Domnall was defeated by Olaf and his ally, the lord of Brega, Domnall mac Congalaich, at the battle of Kilmona (Westmeath), one of the noteworthy battles of Domnall's reign. In revenge, he attacked Domnall mac Congalaich's territory and raided the monasteries of Monasterboice and Dunleer (Louth). His discomfiture at Kilmona emboldened his rivals and in the following year his troops were expelled from Meath by its ruling dynasty, Clann Cholmáin. Shaken but not discouraged, Domnall responded by leading a large army south. First, he destroyed the fortresses and churches of Clann Cholmáin, then he moved into Leinster and raided the territories of the Uí Failgi and Fothairt. Domnall's show of power seems to have had the desired effect and never again was he challenged. In 977 he raided the neighbouring Cenél Conaill and killed Gilla Coluim ua Canannáin. That same year, however, his sons Muirchertach and Congalach were slain by his old enemy, Olaf of Dublin.
By now Domnall's mind was turning from earthly to spiritual matters and there is no indication that he attempted to avenge the death of his sons. He retired into religious life at Armagh (the source of his alternative name, Domnall of Armagh) and died in 980 after a lengthy penance; he was buried there. Domnall's wife was Echrad, the daughter of Matadán mac Áeda, king of Ulster. Their son was Muirchertach (d. 977), but the most renowned of his children was Áed, king of Ailech (r. 9891004), the identity of whose mother is not known. His other known children were Congalach (d. 977), Muiredach, and a second son named Áed, the practice of giving the same name to two children being not uncommon among the Irish aristocracy.
Benjamin T. Hudson
Ann. Ulster · M. C. Dobbs, ed. and trans., The Ban-shenchus [3 pts], Revue Celtique, 47 (1930), 283339; 48 (1931), 163234; 49 (1932), 43789 · K. Meyer, Das Ende von Baile in Scáil, Zeitschrift für Celtische Philologie, 12 (1918), 2328 · J. H. Todd, ed. and trans., Cogadh Gaedhel re Gallaibh / The war of the Gaedhil with the Gaill, Rolls Series, 48 (1867) · M. A. O'Brien, ed., Corpus genealogiarum Hiberniae (Dublin, 1962) · E. Hogan, Onomasticon Goedelicum (1910) · W. M. Hennessy, ed. and trans., Chronicum Scotorum: a chronicle of Irish affairs, Rolls Series, 46 (1866) · AFM · D. Ó Corráin, Ireland before the Normans (1972)