The French reconnoitering parties found no way open to attack the English unless under grievous disadvantages. The Cardinals of Tusculum, St. John, and St. Paul endeavored to negotiate terms of peace, and commissioners on both sides met. The terms offered by Philip were, however, by no means so favorable as Edward, after his own victorious operations and those of his armies in Brittany and Guienne, had a right to expect, and the negotiations were broken off. The following day the French king sent in a message to Edward saying that he had examined the ground in every direction in order to advance and give battle, but had found no means of doing so. He therefore summoned the king to come forth from the marshy ground in which he was encamped and to fight in the open plain; and he offered to send four French knights, who, with four English of the same rank, should choose a fair plain in the neighborhood, according to the usages of chivalry. Edward had little over thirty thousand men with him; but the same evening that Philip's challenge was received a body of seventeen thousand Flemings and English, detached from an army which had been doing good service on the borders of Flanders, succeeded in passing round the enemy's host and in effecting a junction with the king's army. Early the next morning, after having consulted with his officers, Edward returned an answer to the French king, saying that he agreed to his proposal, and inclosed a safe-conduct for any four French knights who might be appointed to arrange with the same number of English the place of battle. The odds were indeed enormous, the French being four to one; but Edward, after the success of Cressy, which had been won by the Black Prince's division, which bore a still smaller proportion to the force engaging it, might well feel confident in the valor of his troops. His envoys, on arriving at the French camp, found that Philip had apparently changed his mind. He declined to discuss the matter with which they were charged, and spoke only of the terms upon which Edward would be willing to raise the siege of Calais. As they had no authority on this subject the English knights returned to their camp, where the news was received with great disappointment, so confident did all feel in their power to defeat the huge host of the French. But even greater was the astonishment the next morning, when, before daylight, the tents of the French were seen in one great flame, and it was found that the king and all his host were retreating at full speed. The Earls of Lancaster and Northampton, with a large body of horse, at once started in pursuit, and harassed the retreating army on its march toward Amiens.