Fifth Crusade
Striking at Egypt first, the crusaders took Damietta, but on the march to Cairo they were trapped by the Nile flood and gave Damietta back.
Pope Innocent III launched this crusade at the Fourth Lateran Council (1215). The crusaders aimed to strike Egypt, heart of the Ayyubid realm, and trade it for Jerusalem; besieging Damietta from 1218, they took it in November 1219. Sultan al-Kamil offered Jerusalem, but the papal legate Pelagius refused.
Marching on Cairo in the summer of 1221, the crusaders were trapped by the rising Nile and dykes cut by the Egyptians, and withdrew after returning Damietta. Francis of Assisi is said to have visited al-Kamil during the campaign.