Up to the taking of Paris by the constable the Duke of Burgundy had kept himself in reserve, and had maintained a tacit neutrality towards England; he had merely been making, without noisy demonstration, preparations for an enterprise in which he, as Count of Flanders, was very much interested. The success of Richemont inspired him with a hope, and perhaps with a jealous desire, of showing his power and his patriotism as a Frenchman by making war, in his turn, upon the English, from whom he had by the treaty of Arras effected only a pacific separation. In June, 1436, he went and besieged Calais. This was attacking England at one of the points she was bent upon defending most obstinately. Philip had reckoned on the energetic cooperation of the cities of Flanders, and at the first blush the Flemings did display a strong inclination to support him in his enterprise. “When the English,” they said, “know that my lords of Ghent are on the way to attack them with all their might they will not await us; they will leave the city and flee away to England.” Neither the Flemings nor Philip had correctly estimated the importance which was attached in London to the possession of Calais. When the Duke of Gloucester, lord-protector of England, found this possession threatened, he sent a herald to defy the Duke of Burgundy and declare to him that, if he did not wait for battle beneath the walls of Calais, Humphrey of Gloucester would go after him even into his own dominions. “Tell your lord that he will not need to take so much trouble, and that he will find me here,” answered Philip proudly. His pride was over-confident. Whether it were only a people’s fickleness or intelligent appreciation of their own commercial interests in their relations with England, the Flemings grew speedily disgusted with the siege of Calais, complained of the tardiness in arrival of the fleet which Philip had despatched thither to close the port against English vessels, and, after having suffered several reverses by sorties of the English garrison, they ended by retiring with such precipitation that they abandoned part of their supplies and artillery. Philip, according to the expression of M. Henri Martin, was reduced to covering their retreat with his cavalry; and then he went away sorrowfully to Lille, to advise about the means of defending his Flemish lordships exposed to the reprisals of the English.