The Sixth Crusade was led by the Holy Roman Emperor Frederick II in 1228 AD. Frederick was an intriguing and exotic person who spoke six languages fluently, including Arabic. He was liked and respected by the Muslims. He enjoyed long-standing friendships with various members of Islamic royalty, kept a harem in Sicily, and was schooled in Arabic philosophy and mathematics. Frederick was known to his contemporaries as Stupor Mundi, the “Marvel of the World.” Frederick II was crowned king of Germany by Pope Innocent in 1215, and immediately announced his intention to go on a Crusade. In 1225, he was married to the daughter and heiress of John of Brienne, king of Jerusalem. John assumed the marriage would encourage Frederick to finally begin his Crusade, but instead he delayed.
In 1227, Pope Honorius III died, and was succeeded by Pope Gregory IX, who immediately ordered Frederick to fulfill his promise to begin the Crusade. Frederick quickly returned however, claiming illness, but Gregory did not believe him. Pope Gregory then excommunicated Frederick for his premature return and for his military efforts against the Templars. Frederick set off again in June 1228, and his resolve to fight a Crusade for two years was initially received with enthusiasm by the Templars and the Hospitalers. Yet soon after his arrival in Acre, a letter from the pope ordered the Templars to play no part in Frederick's efforts because of his excommunication. The pope soon sent another letter to the Templars announcing that he had just excommunicated Frederick a second time. The Templars were now presented with a problem, for it was forbidden for an excommunicate to take part in a Crusade.
Although the Templars were bound by their vows of obedience to the pope, they knew that any changes Frederick might make with the Muslims would effect the balance of power in the Holy Land. Therefore they needed full knowledge of his actions, and in the event of any military or territorial gains, they wanted to be included. Thus the Templars decided on a compromise: they rode one day's journey behind Frederick so they could not be accused of marching with him. Later they marched alongside him. The terms of this arrangement were that Frederick would state that his orders were being given in the name of God, rather than in his own name, that of an excommunicated emperor.
In February 1229, Frederick negotiated a ten year treaty with al-Kamil for the return of Jerusalem and a portion of the land leading to the Mediterranean. In addition, the sultan agreed to the return of Nazareth, western Galilee, and the lands around Sidon and Bethlehem. In March 1229, Frederick crowned himself king of Jerusalem. The very next day, the archbishop of Caesarea excommunicated the entire city of Jerusalem for harboring the excommunicated emperor. Although Frederick negotiated his treaty in the name of all Franks, he never received their permission to do so. The Templars were angry that the site of their original Temple would remain in Muslim hands. The holy war against the infidel was the raison d'etre of the military orders, and Frederick had just undermined it. Feelings were so tense between him and the Templars that he feared for his life and so he left Jerusalem.
The Templars joined in a plan with the patriarch of Jerusalem to take back Jerusalem in the name of the pope. However, Frederick learned of their activities and called them traitors. He also expelled them from Acre, and disarmed them to the extent that he was able. He helped strengthen the newly arrived Teutonic Knights, a German military order founded in 1198, and patterned after the Templars. Meanwhile, the pope had undertaken a Crusade against Frederick in Italy, and the Templars tried to persuade sultan al-Kamil to turn against Frederick. Finally, on May 1, 1229, the pressure from the pope forced Frederick to return to Europe. Thus the Sixth Crusade lasted from 1228-1229 AD, one year.
References:
Adduson, C.G. The Knights Templars. (Forgotten Books, 2012).
Haag, M. The Templars: History & Myth. (London, England: Profile Books, 2008).
Robinson, J.J. Dungeon, Fire & Sword. (Lanham, Maryland: The Rowman & Littlefield Publishing Group Inc., 2009).
Wasserman, J. The Templars and the Assassins. (Rochester, Vermont: Inner Traditions, 2001).
