The two armies marched over the Low Countries and Flanders, seeking out both of them the most favorable position for commencing the attack. On Sunday, the 27th of August, 1214, Philip had halted near the bridge of Bouvines, not far from Lille, and was resting under an ash beside a small chapel dedicated to St. Peter. There came running to him a messenger, sent by Guerin, Bishop of Senlis, his confidant in war as well as government, and brought him word that his rear-guard, attacked by the Emperor Otho, was not sufficient to resist him. Philip went into the chapel, said a short prayer, and cried as he came out, “Haste we forward to the rescue of our comrades!” Then he put on his armor, mounted his horse, and made swiftly for the point of attack, amidst the shouts of all those who were about him, “To arms! to arms!”
Both armies numbered in their ranks not only all the feudal chivalry on the two sides, but burgher-forces, those from the majority of the great cities of Flanders being for Otho, and those from sixteen towns or communes of France for Philip Augustus. It was not, as we have seen, the first time that the forces from the French rural districts had taken part in the king’s wars; Louis the Fat had often received their aid against the tyrannical and turbulent lords of his small kingdom; but since the reign of Louis the Fat the organization and importance of the communes had made great progress in France; and it was not only rural communes, but considerable cities, such as Amiens, Arras, Beauvais, Compiegne, and Soissons, which sent to the army of Philip Augustus bodies of men in large numbers and ready trained to arms. Contemporary historians put the army of Otho at one hundred thousand, and that of Philip Augustus at from fifty to sixty thousand men; but amongst modern historians one of the most eminent, M. Sismondi, reduces them both to some fifteen or twenty thousand. One would say that the reduction is as excessive as the original estimate. However that may be, the communal forces evidently filled an important place in the king’s army at Bouvines, and maintained it brilliantly. So soon as Philip had placed himself at the head of the first line of his troops, “the men of Soissons,” says William the Breton, who was present at the battle, “being impatient and inflamed by the words of Bishop Guerin, let out their horses at the full speed of their legs, and attacked the enemy. But the Flemish knights prick not forward to the encounter, indignant that the first charge against them was not made by knights, as would have been seemly, and remain motionless at their post. The men of Soissons, meanwhile, see no need of dealing softly with them and humoring them, so thrust them roughly, upset them from their horses, slay a many of them, and force them to leave their place or defend themselves, willy nilly. At last, the Chevalier Eustace, scorning the burghers and proud of his illustrious ancestors, moves out into the middle of the plain, and with haughty voice, roars, “Death to the French!” The battle soon became general and obstinate; it was a multitude of hand-to-hand fights in the midst of a confused melley. In this melley, the knights of the Emperor Otho did not forget the instructions he had given them before the engagement: they sought out the King of France himself, to aim their blows at him; and ere long they knew him by the presence of the royal standard, and made their way almost up to him. The communes, and chiefly those of Corbeil, Amiens, Beauvais, Compiegne, and Arras, thereupon pierced through the battalions of the knights and placed themselves in front of the king, when some German infantry crept up round Philip, and with hooks and light lances threw him down from his horse; but a small body of knights who had remained by him overthrew, dispersed, and slew these infantry, and the king, recovering himself more quickly than had been expected, leaped upon another horse, and dashed again into the melley. Then danger threatened the Emperor Otho in his turn. The French drove back those about him, and came right up to him; a sword thrust, delivered with vigor, entered the brain of Otho’s horse; the horse, mortally wounded, reared up and turned his head in the direction whence he had come; and the emperor, thus carried away, showed his back to the French, and was off in full flight. “Ye will see his face no more to-day,” said Philip to his followers: and he said truly.