Ireland Under Strain
Donnchad mac Briain, a son of Brian Bóruma, remained the leading king of Munster. Earlier in his reign he had projected power into Leinster, Dublin, Mide and Connacht, and an inscription on the shrine of the Stowe Missal styled him king of Ireland. By 1057, however, such a claim was increasingly difficult to sustain. His principal external opponent was Diarmait mac Maíl na mBó, king of Leinster and overlord of Dublin, while serious danger also came from within the wider Uí Briain family.