 In January 1364 Charles met Edward, the Black Prince at Agen in order to negotiate the passage of his troops through the English-held duchy of Aquitaine, to which the Prince agreed perhaps because of his friendship with Charles's new military adviser Jean III de Grailly, captal de Buch, who had been betrothed to Charles' sister and was to lead his army to Normandy.In March 1364 the Captal marched towards Normandy to secure Charles's domains.John II of France had returned to London to negotiate with Edward III, and the defence of France was once more in the hands of the Dauphin.