The young Count of Flanders, who, at the death of his father at Cressy, was sixteen years of age, was naturally even more hostile to the English than the late prince had been, and he strove to win over his subjects to the French alliance, while Phillip made them magnificent offers if they would join him.

The Flemings, however, remained stanch to the English alliance, and held their prince in duresse until he at last consented to marry the daughter of Edward.

A week before the date fixed for the nuptials, however, he managed to escape from the vigilance of his guards when out hawking, and fled to the court of France.
In Scotland Phillip was more successful, and David Bruce, instead of employing the time given him by the absence of Edward with his armies in driving out the English garrisons from the strong places they still held in Scotland, raised an army of 50,000 men and marched across the border into England plundering and ravaging.

Queen Philippa, however, raising an army, marched against him, and the Scotch were completely defeated at Neville's Cross, 15,000 being killed and their king himself taken prisoner.
Walter's conduct at the battle of Cressy gained him still further the favour of the Black Prince.

The valour with which he had fought was conspicuous even on a field where all fought gallantly, and the prince felt that more than once he would have been smitten down had not Walter's sword interposed.