These unexpected successes roused Philip to strenuous efforts, and a hundred thousand men gathered under his son, John, Duke of Normandy, for the subjugation of the South.

Angouleme was won back, and Aiguillon besieged when Edward sailed to the aid of his hard-pressed lieutenant.

It was with an army of thirty thousand men, half English, half Irish and Welsh, that he commenced a march which was to change the whole face of the war.

His aim was simple.

Flanders was still true to Edward's cause, and while Derby was pressing on in the south a Flemish army besieged Bouvines and threatened France from the north.