In 934 Æthelstan invaded Scotland. His reasons are unclear, and historians give alternative explanations. The death of his half-brother Edwin in 933 might have finally removed factions in Wessex opposed to his rule. Guthfrith, the Norse king of Dublin who had briefly ruled Northumbria, died in 934; any resulting insecurity among the Danes would have given Æthelstan an opportunity to stamp his authority on the north. An entry in the Annals of Clonmacnoise, recording the death in 934 of a ruler who was possibly Ealdred of Bamburgh, suggests another possible explanation, a dispute between Æthelstan and Constantine over control of Bamburgh. The Anglo-Saxon Chronicle briefly recorded the expedition without explanation, but the twelfth-century chronicler John of Worcester stated that Constantine had broken his treaty with Æthelstan.
in 934 æthelstan invaded scotland his reasons are unclear and historians give alternative explanations the death of his half-brother edwin in 933 might have finally removed factions in wessex opposed to his rule guthfrith the norse king of dublin who had briefly ruled northumbria died in 934; any resulting insecurity among the danes would have given æthelstan an opportunity to stamp his authority on the north an entry in the annals of clonmacnoise recording the death in 934 of a ruler who was possibly ealdred of bamburgh suggests another possible explanation a dispute between æthelstan and constantine over control of bamburgh the anglo-saxon chronicle briefly recorded the expedition without explanation but the twelfth-century chronicler john of worcester stated that constantine had broken his treaty with æthelstan