Domnall Midi - King of Tara

King of Tara

In 743 Domnall defeated and killed Áed Allán and a number of kings of the Airgíalla, perhaps at Mag Sered near Kells, although some annals place the battle in modern County Longford, either location suggesting that Áed was the aggressor. The annals offer no explanation as to why the two were at war, but it has been suggested that Áed's expansion into the lands of the Conailli Muirthemne (in modern County Louth) or the killing of Conaing mac Amalgado, king of Brega, supposedly strangled by Áed in 742, may have been connected to Domnall's return.

Having defeated Áed, the Annals of Ulster state that Domnall again entered the religious life in 744. When Flaithbertach's son Áed Muinderg died in 747, the Annals of Ulster call him "king of the North", suggesting that he was Domnall's deputy among the northern Uí Néill. Domnall seems also to have had a deputy in the south. His distant kinsman Fallomon mac Con Congalt of Clann Cholmáin Bicc may have been king of Mide in 733, and is definitely styled as such at his death in 766.

Other than this, almost nothing is recorded of Domnall during the twenty years in which he is reckoned to have been High King of Ireland. Unlike Áed Allán, he maintained good relations with the Uí Dúnlainge kings of Leinster. In 753 he is said to have imposed the "law of Columba" on behalf of Sléibéne, Abbot of Iona. Domnall's support for Iona, a policy followed by his descendants, would eventually see the principal Columban church move to Kells during the Viking Age.

There is only one report of Domnall at war, this in 756. The Annals of Ulster report that Domnall led an army from Leinster into Conailli Muirthemne. This again suggests that he saw the presence of the Cenél nEógain on the eastern coast as a threat to his family's power and also underlines the good relations he enjoyed with the kings of Leinster.

Domnall died in 763 and was buried at the Columban monastery of Durrow in present-day County Offaly. Although he enjoyed good relations with Iona and was seemingly devout, he was not well regarded by all Irish churchmen. The Félire Óengusso, written at Tallaght in the borderlands of Leinster, apparently includes him among the oppressive secular rulers whom the authors held in contempt.