Philip now set about humbling the proud city in grim earnest, cutting off the commerce upon which its prosperity depended, and even its food supplies. To add to the horrors of the siege the plague broke out within the city, while leprosy was also prevalent. No less than twenty-four thousand died of pestilence and famine before the brave burghers at last gave in. Philip's terms were hard. The city officials were required to meet him bareheaded and barefooted the next time he deigned to visit the defeated commune, and on their knees give him the keys of the city. A heavy fine was imposed and forty-two leading burghers were excluded from amnesty and beheaded--including Van de Walle, who had saved his life at the Bouverie gate. This was the "Great Humiliation," as it is sometimes called, but--finding that continued hostility to the chief trading centre in his dominions was driving foreign traders away--the Duke now took Bruges again into his favour and never again molested it during his long reign. The proud city of Ghent was the next to feel the weight of the powerful Duke's displeasure. Rebelling in 1448 against the imposition of a tax on salt, called the gabelle, the city defied the Duke's authority for five years. Meanwhile Philip gradually cut off its supplies, as he had done with Bruges. Ghent was more populous, however, and its burgher armies took the field and carried open war as far as Audenaerde, which they besieged. Several small battles were fought, the advantage resting mainly with the Duke, until on July 23, 1453, the decisive conflict took place. The Duke's forces were encamped at Gavre, a few miles from the city. Spies within the gates told the burghers that it would be easy to surprise the camp and destroy Philip's army. The tocsin therefore was sounded and the hosts of guildsmen and burghers marched out to attack the enemy. The Duke's forces, aware of the manner in which the Flemings were to be betrayed, were placed where the open ground favoured the Burgundian horsemen. In spite of this advantage, the contest was a stubborn one, both the Duke and his son Charles narrowly escaping death on one occasion. At last the Flemings began to give way, and the battle became a slaughter, more than twenty thousand of the guildsmen being slain on the field, while all prisoners were hanged. This struggle was called "the red sea of Gavre." As the men of Ghent were fleeing toward their city Philip sought to pursue them by the shortest way and intercept their flight. He accordingly called for a guide. A peasant of the neighbourhood volunteered, and, after leading the Burgundian army across fields and by-paths for several hours, conducted the victors--not to the gates of Ghent, but back to their own camp again! This nameless hero was incontinently hanged to the nearest tree, but he no doubt saved the city from pillage and rapine that night.