More serious causes of resentment came to aggravate a situation already so uncomfortable. The war, which had been a-hatching ever since the imperial election at Frankfort, burst out in 1521, between Francis I. and Charles V. Francis raised four armies in order to face it on all his frontiers, in Guienne, in Burgundy, in Champagne, and in Picardy, “where there was no army,” says Du Bellai, “however small.” None of these great commands was given to the Duke of Bourbon; and when the king summoned him to the army of Picardy, whither he repaired in all haste with six thousand foot and three hundred men-at-arms raised in his own states, the command of the advance-guard, which belonged to him by right of his constableship, was given to the Duke of Alencon, who had nothing to recommend him beyond the fact that he was the husband of Marguerite de Valois and brother-in-law of the king. Bourbon deeply resented this slight; and it was remarked that he frequently quoted with peculiar meaning a reply made by a Gascon gentleman to King Charles VII., who had asked him if anything could shake his fidelity, “Nothing, sir, nothing; not even an offer of three such kingdoms as yours; but an affront might.” The constable did not serve a whit the less valiantly and brilliantly in this campaign of Picardy; he surprised and carried the town of Hesdin, which was defended by a strong garrison; but after the victory he treated with a generosity which was not perhaps free from calculation the imperialist nobility shut up in the castle; he set all his prisoners at large, and paid particular attention to the Countess de Roeux, of the house of Croy, whom he knew to have influence with Charles V. He was certainly not preparing just then to abandon the King of France and go over to the camp of the emperor; but he was sufficiently irritated against Francis I. to gladly seize an opportunity of making new friends on the rival side.