Afterwards, the last opposition remaining in Munster was an alliance consisting of the rebellious Irish led by Donnubán (Donovan), the man responsible for Mathgamain's death, and the remaining Norse/Viking forces, possibly led by Ivar's last remaining son and designated successor, Aralt (Harold). Brian attacked them at the Battle of Cathair Cuan, which may have been either a single battle or an extended conflict over the period 977–978. In any case, the event is mentioned in the Annals, and the later source the "Cogadh" describes Brian Brian making a "great slaughter" of his enemies, killing both Donnubán and Aralt, and securing his position within the province.