The Battle Hostile_encounter of Brunanburh was fought Hostile_encounter in 937 between Æthelstan , King of England , and an alliance of Olaf Guthfrithson , King of Dublin ; Constantine II , King of Scotland and Owain , King of Strathclyde .

Following an unchallenged invasion Military_operation of Scotland by Æthelstan in 934 , possibly launched Process_start because Constantine had violated Legality a peace treaty , it became Becoming apparent that Æthelstan could be defeated Hostile_encounter only by an alliance of his enemies .

Following an unchallenged invasion Military_operation of Scotland by Æthelstan in 934 , possibly launched Process_start because Constantine had violated Legality a peace treaty , it became Becoming apparent that Æthelstan could be defeated Hostile_encounter only by an alliance of his enemies .

In August 937 Olaf and his army sailed Motion from Dublin to join Participation forces with Constantine and Owen , but the invaders were routed in the battle against Æthelstan .

Æthelstan 's victory preserved Preserving the unity of England .