In 1339 he accompanied the King to Flanders. He served variously in Brittany and in Scotland, and was present at the great English victories at Sluys and was a commander at Crécy. His most stunning feat was commanding an English force to victory against a much bigger French force at the Battle of Morlaix in 1342. Some of the details are in dispute, but it is clear that he made good use of pit traps, which stopped the French cavalry.