Rival Overkings
Archived: 26 September 2026
In 1100 Ireland remained divided among local and provincial kings, as Muirchertach Ua Briain of Munster and Domnall Ua Lochlainn of Ailech contested supremacy. Muirchertach’s northern expedition to Eas Ruaidh failed, Leinster raided Airgialla, and Dublin’s fleet was destroyed in Inis Eógain. Domnall retaliated by ravaging Brega and Fine Gall and captured Donnchad Ua hEochada, king of Ulaid. Deaths of rulers and churchmen altered regional politics. Warfare burdened rural communities, while Dublin’s maritime economy remained important. Monasteries sustained learning, pilgrimage and mediation. Neither overking prevailed; their struggle intensified before Muirchertach’s major 1101 campaign, which devastated Ailech and displayed southern power.