A little over a hundred years earlier, Pope Urban II had told the Knights of Europe, that it was a crime to kill Christians, for the purpose of the crusade was to free up the Holy Land for Christian pilgrims.
The Fourth Crusade, led by knights not kings under the direction of Pope Innocent III, had no compunction about killing Christians who actively stood in their way. In the beginning knights just ignored requests by the Pope not to kill Christians, but he was not standing with them, and his requests fell on deaf ears.
With the disaster of the Fourth crusade behind them, Pope Innocent III called for a new crusade, which was made up of many Christian citizens, as many European leaders were busy fighting each other.
In 1217, the Crusader army headed to Acre and joined up with John of Brienne current ruler of the Kingdom of Jerusalem, and Prince Bohemund IV of the kingdom of Antioch. Their combined forces would do battle against the Ayyubids state of Egypt.
With minimal success, they were joined by the armies of Germany and Holland, in re-taking Jerusalem. Oliver of Cologne and William I the Count of Holland arrived to conqueror Egypt. They allied themselves with the Seljuk Sultan of Rum, who attacked Egyptians from the north.
In June of 1218, the crusaders attacked Damietta, an Egyptian settlement, taking several months of hard fighting, with the loss of thousands of lives. As victors they looted Damietta, giving them the inspiration to take on Cairo.
The Sultan Al-Adil came face to face with the crusader army a few miles outside of Damietta. Egyptian forces moved closer to Cairo and the Nile. As the crusaders neared Cairo, they became trapped by the water’s, and were forced to retreat.
The Sultan Al-Adil’s army captured the larger crusader force, because they knew their landscape and the water’s well. Damietta was returned to the Sultan, as the fifth crusade drew to a close.
(Image) Fifth Crusade: Wikipedia