Domnall Ua Lochlainn

The meaning, and even the definition, of the High Kingship of Ireland to which Domnall laid claim was far from clear in the period after the death of the last traditional Uí Néill king of Tara, Máel Sechnaill mac Domnaill of Clann Cholmáin, in 1022.

[2] Regardless of legal frictions, the first king to construct something resembling an over-lordship of Ireland after the death of Máel Sechnaill was Diarmait mac Maíl na mBó of the Uí Cheinnselaig.

His son Murchad ruled Dublin, Toirdelbach Ua Briain in Munster was his client, and Niall mac Eochada of Ulster was his ally.

[7] Domnall became king of Ailech in 1083 and began his reign in traditional fashion, with an inaugural raid—crech ríg—against the Conaille Muirthemne (in the region of modern Dundalk, County Louth).

Domnall's glowing obituary in the Annals of Ulster reads as follows:Domnall son of Ardgar son of Lochlann, over-king of Ireland, pre-eminent among the Irish in form and lineage, in sense and valour, in happiness and prosperity, in giving valuables and food, died in Daire Coluim Cille in the thirty-eighth year of his reign, the seventy-third year of his age, on Wednesday night, the fourth of the Ides [i.e. 10 February 1121] and the eighteenth of the moon, the feast of Mo-Chuaróc the wise.