Battle of Degsastan
The
Battle of Degsastan was fought in
603 AD between the
Anglo-Saxon king
Aethelfrith of Northumbria and the Scots under
Aedan of Dalriada. Aethelfrith carried the day, but we know almost nothing else about the battle, not even where "Degsastan" was supposed to be.
Aethelfrith and went on to establish Northumbria as the union of Bernicia and Deira, while the Scots refrained from attacking the English for many years thereafter.
Reference