The forces of Olaf Guthfrithson were defeated by the English led by Æthelstan at a battle fought in which year ?
Olaf Guthfrithson:  The forces of Olaf and Constantine were defeated by the English led by Æthelstan at the Battle of Brunanburh. Battle of Brunanburh: The Battle of Brunanburh was fought in 937 between Æthelstan, King of England, and an alliance of Olaf Guthfrithson, King of Dublin; Constantine, King of Alba and Owen, King of Strathclyde.
i don't know