So I'm working on a project for class and I was assigned to figure out how prisoners were treated during the Fifth Crusade.
The books my professor assigned include nothing about prisoner's during the Fifth Crusade. I looked on Google, Google Scholar, my university's library website, but I got nothing. All I can find is prisoner treatment throughout the Crusades in general, but nothing specific to the Fifth Crusade. I'm not asking you guys to do my homework, just to give me a brief idea if you happen to know anything related to the topic or if you can point to a site/book that would have the information.
The goal of the Fifth Crusade had been to recapture Jerusalem by way of Egypt. The Crusaders initially made some progress, managing to capture and hold the port of Damietta. But as they prepared to march further, to Cairo, the army was cornered by floodwaters: perhaps natural, perhaps orchestrated by the sultan. They were forced to surrender. The terms of the settlement allowed the Christians their freedom--but at the cost of Damietta.
You will find some information about the treatment of prisoners of war specific to the Fifth Crusade if you investigate this surrender and the loss of Damietta.
Let me know if you need some more direction, but this should get you started with better search terms.