To have become Duke of Burgundy would have given Charles the position at the centre of French politics that he had always craved, and the abrupt dismissal of his claim provoked fresh bitterness. After the failure of an attempt to win the Pope to his claim, Charles returned to his kingdom of Navarre in November 1361. He was soon plotting afresh to become a power in France. A planned rising of his supporters in Normandy in May 1362 was an abject failure, but in 1363 he evolved an ambitious plan to form two armies in 1364, one of which would go by sea to Normandy and the other, under his brother Louis, would join forces with the Gascons operating with the Great Company in Central France and invade Burgundy, thus threatening the French King from both sides of his realm. 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.