The next morning, at a very early hour, the men were called to arms again. A new assaulting force was organized, and at sunrise the trumpet sounded the order for them to advance to the attack. Prince Edward himself took the command at this trial, and by his presence and his example incited the men to make the greatest possible efforts to batter down the gates and to scale the walls. Edward was excited to a high degree of resentment and rage against the garrison of the castle, not only on account of the general obstinacy of their resistance, but because, on the preceding day, a squire, who was attendant upon him, and to whom he was strongly attached, was killed at his side by a stone hurled from the castle wall. When he saw this man fall, he took a solemn oath that he would never leave the place until he had the castle and all that were in it in his power. But, notwithstanding all the efforts of his soldiers, the castle still held out. Edward's troops thronged the margin of the ditch, and shot arrows so incessantly at the battlements that the garrison could scarcely show themselves for an instant on the walls. Finally, they made hurdles and floats of various kinds, by means of which large numbers succeeded, half by swimming and half by floating, to get across the ditch, and then began to dig in under the wall, while the garrison attempted to stop their work by throwing down big stones upon their heads, and pots of hot lime to eat out their eyes. At another part the besiegers constructed great engines, such as were used in those days, in the absence of cannon, for throwing rocks and heavy beams of wood, to batter the walls. These machines also threw a certain extraordinary combustible substance called Greek fire. It was this Greek fire that, in the end, turned the scale of victory, for it caught in the lower court of the castle, where it burned so furiously that it baffled all the efforts of the besieged to extinguish it, and at length they were compelled to surrender. Edward made the principal commanders prisoners, but he let the others go free. The castle itself he utterly destroyed. Having thus finished this work, Edward resumed his march, passing on to the westward through Touraine, to avoid the French king, who he knew was coming down upon him from the direction of Chartres at the head of an overwhelming army. King John advanced to the Loire, and sending different detachments of his army to different points, with orders to cross at any bridges that they could find, he himself came to Blois, where he crossed the river to Amboise, and thence proceeded to Loches. Here he learned that the English were moving off to the westward, through Touraine, in hopes to make their escape. He set off after them at full speed. He had four sons with him in his army, all young men. Their names were Charles, Louis, John, and Philip. At length the two armies began to approach each other near the town of Poictiers.