The war party had now gained the upper hand at the French court; in 1403 preparations were made to attack Calais, and a Breton fleet put to sea.

At the news of its presence in the Channel Henry Percy and the Earl of Worcester at once rose in the north and struck across England to join Owen Glyndwr in Wales, while the Earl of Northumberland gathered a second army and advanced more slowly to their support.

But Glyndwr was still busy with the siege of Caermarthen, and the king by a hasty march flung himself across the road of the Percies as they reached Shrewsbury.

On the twenty-third of July a fierce fight ended in the defeat of the rebel force.

Henry Percy was slain in battle, the Earl of Worcester taken and beheaded; while Northumberland, who had been delayed by an army under his rival in the north, Neville, Earl of Westmoreland, was thrown into prison, and only pardoned on his protestations of innocence.