After stalling out at the strategically important but ultimately indefensible port of Damietta, the Crusaders were left with little option but to bid a retreat with no gains to show for their efforts, even with the Ayyubid sultanate of Egypt facing incursions on two fronts, with the previously unseen Mongols on their eastern boundaries. This threat is indeed not for another, separate story-line but folds fundamentally into our present narrative directly. The Crusader States in Cyprus and the Holy Land did not merely evaporate after Frederich II’s failed mission. The doubly-excommunicated Holy Roman Emperor was an Islamophile, having been exposed to the culture and religion early on in his court at Sicily and managed to negotiate a truce with the Egyptian armies that allowed the meagre holdings in the Near East to survive for almost another tumultuous fifty years.
Warrior pilgrims from Europe, however, were not content to be just tolerated under the conditions of standing treaties and came for a fight. The integration and cooperation, even if it was mainly kept up in order to vouchsafe trading-relations, was a bit of a revulsion for the newly-arrived and for leaders back in Europe, fatigued by their own civil-strife and lacking the will to bolster any harmonious middle-ground—as we have seen the Crusaders themselves do rather inexplicably time and time again when settlements of the Holy City of Jerusalem were offered and refused.
Though under continued threat externally and prone to the same problems of succession internally and civil war, the Crusader States had achieved somewhat of a happy equilibrium, similar to the case after the debacle of the Fourth Crusade and long-lull in adventuring. To the East, however, dust was stirred under hoof of the massive, unstoppable Mongol army, grandson of Genghis Khan, a talented and merciless general called Hülegü dispatched to conquer Persian and the Levant and expand the empire. Shocking, the Mongols sacked and utterly destroyed the ancient city of Baghdad and were making advances at Damascus and Cairo. The only lands that emerged from Hülegü’s wake unscathed were those that wisely, unhesitatingly surrendered, like the Kingdom of Armenia, without a fight and agreed to pay tribute and join the Mongol thrust. The ruthlessness and totality of destruction to the Muslim cities outdid even the worst of the Crusaders, but in a strange twist of history Hülegü spared the Christian inhabitants, allowing their churches to stand and for them to retain their property where all others were toppled and quickly relieved of the wealth and lives. The Buddhist khan had strong Christian sympathies due to the influence of his mother and number-one wife, who were both Nestorians, members of the Assyrian Church of the East.
Hülegü even returned lands that had been recently taken by the Egyptians back to the Principality of Antioch, and later traveled to Rome himself for a papal audience to urge a union of Mongols and Latin Christians to retake Jerusalem. It’s hard to say why this offer was not well received back in Europe—maybe Rome felt that the Nestorian influence was too radical and heretical to invite in. Had that project been undertaken or had the Mameluke armies, usurpers of the sultanate, not been able to turn the tide of battle at the walls of Cairo at Ayn Jalut (the Springs of Goliath), the Mongols eventually bidden to leave the desert so that their horses could graze, the world we’ve inherited, I think, would have looked very different. Once Egypt was able to recover from that harrowing clash, the Mameluke sultan, Baibars, attacked the Crusader States, chipping away at them over the years until they were no longer sustainable, first as punishment for having sided with the Mongols and then for violence unleashed upon the resident merchant population of the Crusader territories.
