The apparently deteriorating situation was no illusion. King Jean II of France had died in England in April 1364 after returning there in lieu of a ransom payment. His ransom remained largely unpaid, and he had failed to ratify a number of territorial concessions owed to the English by the terms of the Treaty of Bretigny. The Dauphin, who succeeded him as Charles V, while physically ill-suited to the battlefield would prove a formidable political opponent. In May 1368 Charles, goaded by fresh attacks from English free companies and sensing the Black Prince’s weakness in Aquitaine, allowed an appeal from a Gascon count against one of the prince’s taxes. This was an expression of overlordship which explicitly breached the terms of the Treaty of Bretigny. Edward wrote to Charles to try to assess his intentions, but received no reply. In November, when a similar incident led Charles to try to summon the prince to court in Paris, it became clear that he was bent on war.

In April 1369 Charles sent Edward a ship carrying a cargo of wine. It was a generous gift which was refused, Charles’ pretence of friendship evidently being nothing more. In reality, in addition to attacks in Gascony, the French were again considering an invasion of England and the Duke of Burgundy was gathering vessels for this purpose. However Charles had underestimated the English, who were under no illusions about his intentions and Calais had been reinforced as early as November 1368. The preliminary build-up of French shipping had also been noticed by English scout ships, and in late January a fleet was ordered to sea for Guy Brian. Despite the official peace, Brian was ordered to ‘resist the malice of our evil enemy of France who exists on the sea’. In March, Charles V officially revealed his scheme to his Great Council, issuing orders for the French fleet to gather in the mouth of the Seine. However, as Chaucer reflected in ‘The Knight’s Tale’, ‘sooth is said ... that feeld hath eyen and the wode hath eres ...’, which was certainly the case at the French court. Before Charles V’s council was even complete, the English government had begun to react.