Defeat at Ard Monann
The dominant figure was Tairdelbach Ua Briain, king of Munster and grandson of Brian Bóruma. Since the death of his former patron, Diarmait mac Maíl na mBó, in 1072, Tairdelbach had worked to extend his influence through Leinster, the midlands and the coastal towns. He was not a king of a united Irish state. His authority rested upon military strength, alliances, hostages, tribute and the management of lesser kings, all of which had to be renewed repeatedly.