Philip VI had assembled a large naval fleet off Marseilles as part of an ambitious plan for a crusade to the Holy Land. However, the plan was abandoned and the fleet, including elements of the Scottish navy, moved to the English Channel off Normandy in 1336, threatening England. To deal with this crisis, Edward proposed that the English raise two armies, one to deal with the Scots "at a suitable time", the other to proceed at once to Gascony. At the same time, ambassadors were to be sent to France with a proposed treaty for the French king.

At the end of April 1337, Philip of France was invited to meet the delegation from England but refused. The arrière-ban, literally a call to arms, was proclaimed throughout France starting on 30 April 1337. Then, in May 1337, Philip met with his Great Council in Paris. It was agreed that the Duchy of Aquitaine, effectively Gascony, should be taken back into the king's hands on the grounds that Edward III was in breach of his obligations as vassal and had sheltered the king's 'mortal enemy' Robert d'Artois. Edward responded to the confiscation of Aquitaine by challenging Philip's right to the French throne.