The Battle of Moira, also known as the Battle of Magh Rath, was fought in the summer of 637 by the High King of Ireland, Domnall II, against his foster son Congal Cáech, King of Ulaid, supported by his ally Domnall Brecc, King of Dál Riata. The battle resulted in a decisive victory for the High King and his army, and Congal Cáech was killed in the fighting.The battle was reputedly fought near the woods of Killultagh just outside the village of Moira in what would become County Down. It was allegedly the largest battle ever fought on the island of Ireland, and resulted in the death of Congal and the retreat of Domnall Brecc. However, the location of the battle is not settled and some commentators identify the location as being a few miles outside Newry, County Down in the vicinity of the townlands of Sheeptown and Derrylecklagh near to the ancient rath known as the Crown Mound.