 Magnús, therefore, appears to have intended for Sigurðr to rule over his recently-won territories.Unfortunately for Ua Briain, and his long-term ambitions in Ireland and the Isles, Magnús was slain in Ulster in 1103, whereupon Sigurðr immediately repudiated his bride and returned to Norway.Although Ua Briain was able to regain control of Dublin, and still held considerable influence in the Isles, Magnús' death appears to have left a power vacuum in the region that he was unable to fill.