The Battle of Degastan in 603CE was a largescale battle between the rival kingdoms of Bernicia and Dál Riada. In the late-6th and early-7th centuries CE, King Æthelfrith of Bernicia had been victorious in a string of battles against native Britons, expanding his already powerful kingdom of Bernicia, which covered most of modern-day Scottish Borders, East Lothian, Berwickshire, Northumberland, and Durham. This expansion frightened King Áedán mac Gabráin of Dál Riada – the Irish-Gaelic kingdom spanning much of western Scotland. Bede’s historical account of the battle (written around 731CE) states that Áedán mac Gabráin led a tremendous force against King Æthelfrith, their armies meeting to do battle at a place now believed to be Dawston, in Liddesdale (about eleven miles from Hawick). Though the Gaels had a much larger force, Bede records the battle as a decisive victory for the Bernician Angles, despite King Æthelfrith losing his brother to it. Victory of the Angles at this monumental fight is probably one of the main reasons for English becoming the language of the eastern Borders, rather than Gaelic.
Although few details are recorded, the two bands are surmised to have met in the valley of the Dawston Burn, close to the road to Kielder Water before it enters England. Another location suggested for the battlefield is ‘Dawstones or Daegstons’, located on the farm of Florida, close to Castleton. And a third suggestion is Dalston near Carlisle.