From all sides the King of France was advised to seize this favourable moment for attacking the Prince. He was told that, as soon as he declared war, all the barons and cities of Aquitaine would turn to his side; for all were discontented with the English rule. At last, on the 25th January, 1369, he summoned the Black Prince to appear before the court of his peers at Paris, and answer the complaints brought against him by his vassals. This proceeding was, of course, entirely contrary to the treaty of Bretigny. It was treating the Prince as if he were a vassal of France; whereas, according to the treaty, the King of France had entirely renounced his claim to the allegiance of Aquitaine. By treating the Black Prince as a vassal, he therefore distinctly threw down the gauntlet of war. Great was the anger of the Prince when this summons reached him. When the commissioners who had brought the letter had read it to him, he looked at them for a moment in silence, and then burst forth in rage. "We will willingly come to Paris on the day appointed," he said; "but it will be with our helmet on our head, and sixty thousand men at our back." He would give no other answer to the commissioners; and after they had gone, his anger burnt so hot against them that he sent some of his knights after them, to seize them and bring them back to prison. "Let them not," he said, "go and tell their prattle to the Duke of Anjou, who loves us little, and say how they have summoned us personally in our own palace." The King of France was indignant when he heard of the answer of the Black Prince, and of the treatment which his commissioners had met with. He made immediate preparations for war. He sent a challenge to the King of England by a common valet, a kitchen-boy, that he might make it as insulting as possible. Both England and its King were sunk in the enjoyments of peace. The King was growing old, and loved ease and luxury. The country was weary of war, and absorbed in trade and manufacture. Still the challenge of the King of France stung their pride, and threw Edward III. into a mighty passion. He determined to reassert his claim to the crown of France, and opened the war with vigour. He sent the Duke of Lancaster with an army to Calais to invade the north of France, and his son Edmund, Duke of Cambridge, with troops to assist the Black Prince in Aquitaine. The Black Prince established his camp at Angoulême. The services of the various Free Companies were eagerly bid for by both the combatants, and many were engaged on either side.