Fifth Crusade
Disaster
The first thing many of the common soldiers did was to get drunk. They evidently could not bear to leave behind them all of their wine, and since they could not bring it with them, they drank it. Consequently, many of them were in various stages of intoxication when the order came to move out. Falling under the heading of "seemed like a good idea at the time", the Teutonic Knights set fire to the supplies in order to deny them to the enemy.
Having been alerted by the flames to the fact that the Christians were retreating, al-Kamil ordered the banks of the canal cut. Water flooded the very ground into which the Christians were retreating and the soldiers quickly found themselves wading through mud or falling into gullies now filled with water. Under these conditions, the Egyptians attacked.
The military orders, and the knights under King John put up a valiant defense and saved what they could of the army. Many of the infantry perished, however, it being unusually difficult to fight at night in the mud when you're drunk. The remnant of the army withdrew to the camp, which now had no supplies thanks to the prompt action of the Teutonic Knights earlier in the evening.
The fleet tried to escape, too. The Nile was running in flood now, so some ships managed to make it through the Egyptian blockade, including one which bore Cardinal Pelagius. From the safety of Damietta he now concluded that all was lost. He opened negotiations with al-Kamil two days later, on August 28. By the 30th, the terms were settled.