Brian was also joined by Óspak, a Norseman, brother of Brodir. Initially the two brothers sailed from the Isle of Man to fight against Brian with the Leinster forces. However, after a disagreement, Brodir planned to kill Óspak and his men the next morning. However Óspak and his soldiers fled during the night with 10 ships and sailed around Ireland to Connacht, where Óspak converted to Christianity and swore allegiance to Brian. He fought on the opposite side to his brother at the battle.