Peter du Bois, knowing these men at arms were in the marshes joining Commines, was not perfectly at his ease, for he was uncertain what might be the event. He had, however, under his command, six or seven thousand men, to whom, during the night, he had thus spoken: “The men at arms who have crossed the river to fight with us are neither of iron nor steel. They have labored hard this whole day, and have been all night standing in these marshes, so that it is possible that toward daybreak they will be overpowered with sleep. While they are in this situation, we will come slyly to attack them. Our numbers are sufficient to surround them, but, when we have so done, let no one dare to rush upon them, but remain silent; for, when it shall be proper time for you to act, I will inform you.” To this command of Peter they all promised obedience. On the other hand, the barons, knights, and squires, who had remained in the marshes so near the enemy, were far from being comfortable: some of them were up to their ankles in mud, and others half way up their legs. But their eagerness and joy, on gaining this pass with so much honor (for very gallant deeds of arms were likely to ensue), made them forget all their pains and difficulties. If it had been in summer-time, instead of the seventh day of November, they would have enjoyed it; but now the ground was cold, muddy, and dirty, and the nights were long. At times also it rained heavily on their heads; but it ran off, as they had their helmets on, and every thing prepared for the combat, and were only waiting for the enemy to come and attack them. The great attention they paid to be in readiness kept up their spirits, and made them almost forget their situation.

The Lord de St. Py full loyally acquitted himself in this expedition, as a scout and observer of what the Flemings were doing, though he was the commander-in-chief. He was continually on the lookout, and went privily to reconnoitre their motions. On his return he said to his companions in a low voice, “Now up: our enemies are very quiet. Perhaps they will advance on us at daybreak: therefore be on your guard, and prepare to act.” He would then return again to see if any thing were going forward, and then come back to tell what he had observed. This he continued to do until the hour which the Flemings had fixed upon to attack them. It was on the point of day when they began their march in close order, without uttering a word. The Lord de St. Py, who was on the watch, no sooner saw this manoeuvre than he found they were in earnest, and, hastening to his companions, said to them, “Now, my lords, be alert: we have but to do our utmost, for our enemy is on his march, and will be instantly here. These barons of new date are advancing slowly, and think to catch and surprise us: show yourselves true men at arms, for we shall have a battle.” As the Lord de St. Py uttered these words, the knights and squires, with great courage, seized their long Bordeaux spears, and, having grasped them with a hasty will, placed themselves in as good order as any knights or squires could devise.

When the Flemings advanced to the combat, the knights and squires began to utter their war-cries, insomuch that the constable and vanguard, who had not yet crossed the bridge, heard them, and said, “Our friends are engaged: may God help them! for at this moment we are unable to give them any assistance.” Peter du Bois marched in front, and was followed by his Flemings; but, when they approached the French, they were received on the sharp points of their long Bordeaux spears, to which their coats of mail made not more resistance than if they had been of cloth thrice doubled; so that they passed through their bodies, heads, and stomachs.

When the Flemings felt these sharp spears which impaled them, they fell back, and the French advancing gained ground upon them; for there were none so hardy but that feared their strokes. Peter du Bois was one of the first who was wounded, and run through by a lance. It came quite out at his shoulder: he was also wounded on the head, and would have been instantly slain if it had not been for the body-guard he had formed, of thirty stout varlets, who, taking him in their arms, carried him as quickly as they could out of the crowd. The mud from the causeway to Commines was so deep that all these people sunk in it up to the middle of their legs. The men at arms, who had been long accustomed to their profession, drove down and slew the Flemings without let or hinderance: they shouted, “St. Py forever!” “Laval,” “Sancerre,” “Anghien!” and the war-cries of others who were there. The Flemings were panic-struck, and began to give way, when they saw these knights attack them so vigorously, and pierce them through with their spears. They retreated, and, falling back on each other, were followed by the French, who marched through them or around them, always attacking the thickest bodies. They no more spared killing them than if they had been so many dogs; and they were in the right, for, had the Flemings conquered, they would have served them the same.

The Flemings, finding themselves thus driven back, and that the men at arms had won the causeway and bridge, counselled together to set fire to the town, in hopes it would cause the French to retreat, or enable them to collect their people. This was executed, and fire set to several houses, which were instantly in flames; but they were disappointed in thinking by this to frighten the French, for they pursued them as valiantly as before, fighting and slaying them on the ground, or in the houses whither they had retreated. Upon this the Flemings made for the open plain, where they collected in a body. They sent to Vertain, Poperingue, Bergues, Rollers, Mesieres, Warneton, and the other neighboring towns, to urge them to come to their assistance at Commines. Those who fled, and the inhabitants of the villages near Commines, began to set their bells a-ringing, which clearly showed there was an engagement going forward. Some of them, however, began to slacken, and others to occupy themselves in saving what they could of their goods, and to carry them to Ypres or Courtray. Women and children ran thither, leaving their houses full of furniture, cattle, and grain. Others again marched in haste toward Commines, to help their countrymen who were fighting.

While this was passing, and those valiant knights who had crossed the Lis in boats were so gallantly engaged, the constable and vanguard were busily employed in attempting to repair the bridge and cross it. There was a very great throng, for the constable had given permission for all to pass it who could. There was much danger for those who crossed it first; and the lords who did so were obliged to step on targets thrown on the beams of the bridge. When they had crossed, they began to strengthen the bridge, for they found the planks lying on the ground, which they put in their proper places. During the night two wagon-loads of hurdles were brought, which were of great use to them, so that shortly it was made as strong as ever. On Tuesday the whole vanguard passed, took possession of the place, and, as they crossed, fixed their quarters in the town.

Those of the vanguard who were in Commines drove out the Flemings. There were slain of them in the streets and fields about four thousand, not including those killed in the pursuit, in windmills, and in monasteries, whither they had fled for shelter; for, as soon as the Bretons had crossed, they mounted their horses, and began a chase after the Flemings, and overran the country, which was then rich and plentiful.