Four years later Edward mounted what was to be his last invasion of Scotland, advancing to the gates of Edinburgh. Bruce had pursued a scorched-earth campaign, denying the enemy essential supplies, so effective that they were forced to retreat by the spur of starvation alone. Once again this provided the signal for a Scottish advance: Bruce, Douglas and Moray crossed the Solway Firth, advancing by rapid stages deep into Yorkshire. Edward and Isabella had taken up residence at Rievaulx Abbey. All that stood between them and the enemy raiders was a force commanded by John de Bretagne, 1st Earl of Richmond, positioned on Scawton Moor, between Rievaulx and Byland Abbey. To dislodge him King Robert used essentially the same tactics as that of Brander in 1308: while Douglas and Moray attacked from the front a party of Highlanders scaled the cliffs on Richmond's flank and attacked from the rear. The Battle of Old Byland turned into a rout, and Edward and his queen were forced into a rapid and undignified flight from Rievaulx, the second time in three years that a Queen of England had taken to her heels.