Olaf married the daughter of Constantine II of Scotland. He also allied himself with Owen of Strathclyde. In 937, Olaf led his allies into battle against Athelstan, king of England, in the Battle of Brunanburh and was decisively defeated.
After Athelstan's death in 939, Olaf again invaded York the same year, forcing Athelstan's successor, Edmund, into a treaty which ceded to Olaf Northumbria and part of Mercia. He did not get to enjoy his new lands for long, dying just two years later in 941. He was succeeded by Olaf Cuaran.
|List of Norse monarchs of Dublin||