He moved along the Severn, securing its towns, advanced westward to Hereford, and was marching at the end of May along bad roads into the heart of South Wales to attack the fortresses of Earl Gilbert in Glamorgan when Edward suddenly made his escape from Hereford and joined Gloucester at Ludlow.

The moment had been skilfully chosen, and Edward showed a rare ability in the movements by which he took advantage of the Earl's position.

Moving rapidly along the Severn he seized Gloucester and the bridges across the river, destroyed the ships by which Leicester strove to escape across the Channel to Bristol, and cut him off altogether from England.

By this movement too he placed himself between the Earl and his son Simon, who was advancing from the east to his father's relief.

Turning rapidly on this second force Edward surprised it at Kenilworth and drove it with heavy loss within the walls of the castle.