 In 868 another of Amlaíb's kinsmen was killed, this time his son Carlus, who died in battle at Killineer (near the Boyne, County Louth), fighting against the forces of Amlaíb's former ally Áed Findliath.This battle was a significant victory for the Northern Uí Néill and is recorded in many Irish chronicles.In retaliation for this defeat Amlaíb raided the monastery at Armagh, which was one of the most important religious sites patronised by the over-kings of the Northern Uí Néill.