History of the Crusades/The Fifth Crusade

Background
After the fiasco of the Fourth Crusade, pope Innocent III called for a new crusade, once more targeting Egypt. The king of Hungary participated briefly, but the core of the army was from Germany, Central Europe, Britain, and Italy rather than France. Frederick II, Holy Roman Emperor, made promises to join the crusade but never did.

Events of the Crusade
The crusaders successfully captured Damietta, a critical port city on the Nile. Faced with this threat to the integral lands of Egypt, the sultan Al-Kamil offered to give Jerusalem to the crusaders in exchange for them evacuating Egypt. The crusaders refused and instead proceeded down to Cairo, but the papal legate ignored the warnings of more seasoned commanders and encamped in a poor position next to the Nile. When the land was flooded by al-Ashraf, the crusaders were trapped and surrendered. As part of the peace deal, in exchange for the return of the prisoners the crusaders were forced to evacuate Damietta and leave Egypt.