Pope Honorius III organized crusading armies led by Leopold VI of Austria and Andrew II of Hungary, and a foray against Jerusalem ultimately left the city in Muslim hands. Later in 1218 a German army led by Oliver of Cologne and a mixed army of Dutch, Flemish and Frisian soldiers led by William I, Count of Holland arrived. In order to attack Damietta in Egypt, they allied with the Seljuk Sultan of Rum in Anatolia, who attacked the Ayyubids in Syria in an attempt to free the Crusaders from fighting on two fronts.
After occupying the port of Damietta, the Crusaders marched south towards Cairo in July of 1221, but were turned back after their dwindling supplies led to a forced retreat. A nighttime attack by Sultan Al-Kamil resulted in a great number of crusader losses and eventually in the surrender of the army. Al-Kamil agreed to an eight-year peace agreement with Europe.
Call to CrusadeEdit
In spring 1213, Pope Innocent III issued the papal bull Quia maior, calling all of Christendom to join a new crusade. The kings and emperors of Europe, however, were preoccupied with fighting among themselves. At the same time, Pope Innocent III did not want their help, because a previous crusade led by kings (the Second Crusade) had failed in the past. He ordered processions, prayers, and preaching to help organize the crusade, as these would involve the general population, the lower nobles, and knights.
The message of the crusade was preached in France by Robert of Courçon; however, unlike other Crusades, not many French knights joined, as they were already fighting the Albigensian Crusade against the heretical Cathar sect in southern France.
In 1215 Innocent III called the Fourth Lateran Council, where, along with the Latin Patriarch of Jerusalem, Raoul of Merencourt, he discussed the recovery of the Holy Land, among other church business. Innocent wanted this crusade to be under the full control of the papacy, as the First Crusade was supposed to have been, in order to avoid the mistakes of the Fourth Crusade, which had been taken over by the Venetians. Innocent planned for the crusaders to meet at Brindisi in 1216, and prohibited trade with the Muslims to ensure that the crusaders would have ships and weapons. Every crusader would receive an indulgence, including those who simply helped pay the expenses of a crusader but did not go on crusade himself.
Germany and HungaryEdit
Oliver of Cologne had preached the crusade in Germany, and Emperor Frederick II attempted to join in 1215. Frederick was the last monarch Innocent wanted to join, as he had challenged the Papacy (and would do so in the years to come). Innocent, however, died in 1216. He was succeeded by Pope Honorius III, who barred Frederick from participating, but organized crusading armies led by Leopold VI of Austria and Andrew II of Hungary.
In Jerusalem, the walls and fortifications were demolished to prevent the Christians from being able to defend the city if they should reach it and take it. Muslims fled the city, afraid that there would be a repeat of the bloodbath of the First Crusade in 1099 . The Ayyubids, however, were not interested in fighting. Nothing came of this, and Andrew, Bohemund, and Hugh returned home in 1218.
Alliance with the Sultanate of RumEdit
Later in 1218 Oliver of Cologne arrived with a new German army and the count of Holland William I arrived with a mixed army consisting of Dutch, Flemish and Frisian soldiers. With Leopold and John they discussed attacking Damietta in Egypt. To accomplish this they allied with Keykavus I, the Seljuk Sultan of Rum in Anatolia, who attacked the Ayyubids in Syria in an attempt to free the Crusaders from fighting on two fronts.
In June of 1218 the crusaders began their siege of Damietta, and despite resistance from the unprepared sultan Al-Adil, the tower outside the city was taken on August 25. They could not gain Damietta itself, and in the ensuing months diseases killed many of the crusaders, including Robert of Courcon. Al-Adil also died and was succeeded by Al-Kamil. Meanwhile, Honorius III sent Pelagius of Albano to lead the crusade in 1219 . Al-Kamil tried to negotiate peace with the crusaders. He offered to trade Damietta for Jerusalem, but Pelagius would not accept these offers. After hearing this Count William I of Holland left the crusade and sailed home. In August or September, Francis of Assisi arrived in the crusader camp and crossed over to preach to al-Kamil. By November, the crusaders had worn out the sultan's forces, and were finally able to occupy the port.
Immediately the papal and secular powers fought for control of the town, with John of Brienne claiming it for himself in 1220 . Pelagius would not accept this and John returned to Acre later that year. Pelagius hoped Frederick II would arrive with a fresh army, but he never did; instead, after a year of inactivity in both Syria and Egypt, John of Brienne returned, and the crusaders marched south towards Cairo in July of 1221 .
By now Al-Kamil was able to ally with the other Ayyubids in Syria, who had defeated Keykavus I. The crusader march to Cairo was disastrous; the river Nile flooded ahead of them, stopping the crusader advance. A dry canal that was previously crossed by the crusaders flooded, thus blocking the crusader army's retreat. With supplies dwindling, a forced retreat began, culminating in a night time attack by Al-Kamil which resulted in a great number of crusader losses and eventually in the surrender of the army under Pelagius.
The terms of this surrender meant the relinquishing of Damietta to Al-Kamil in exchange for the release of the crusaders. Al-Kamil agreed to an eight year peace agreement with Europe and to return a piece of the true cross (which, as it turned out, Al-Kamil didn't possess).