King Edward found no difficulty in awakening the war spirit of England anew, for the King of France, in an act of infamous treachery, in despite of the solemn terms of the treaty, excited against himself the indignation not only of England but of all Europe.

Oliver de Clisson, with fourteen other nobles of Brittany and Normandy, were arrested by his order, taken to Paris, and without form of trial there decapitated.
This act of treachery and injustice aroused disgust and shame among the French nobles, and murmurs and discontent spread throughout the whole country.
In Brittany numbers of the nobles fell off from the cause of Charles of Blois, and King Edward hastened his preparations to avenge the butchery of the adherents of the house of Montford.

Phillip, however, in defiance of the murmurs of his own subjects, of the indignant remonstrances of Edward, and even those of the pope, who was devoted to his cause, continued the course he had begun, and a number of other nobles were seized and executed.

Godfrey of Harcourt alone, warned by the fate of his companions, refused to obey the summons of the king to repair to Paris, and fled to Brabant.

His property in France was at once seized by Phillip; and Godfrey, finding that the Duke of Brabant would be unable to shield him from Phillip's vengeance, fled to the English court, and did homage to Edward.
On the 24th of April, 1345, Edward determined no longer to allow Phillip to continue to benefit by his constant violations of the truce, and accordingly sent a defiance to the King of France.
De Montford, who had just succeeded in escaping from his prison in Paris, arrived at this moment in England, and shortly afterwards set sail with a small army under the command of the Earl of Northampton for Britanny, while the Earl of Derby took his departure with a larger force for the defence of Guienne.
King Edward set about raising a large army, which he determined to lead himself, but before passing over to France he desired to strengthen his hold of Flanders.