After the Anatolian defenses were overwhelmed and destroyed by the Mongolian armies, the Crusader States, and the Ayyubids we're next to suffer the full might of the Great Khan's armies. The other neighboring countries, the Ziyalid Sultanate in Egypt and the Nahjanid Sultanate of Yemen, while not involved in the conflict they were threatened by the war and it's possible spillovers, along with the disruption of formerly profitable trade rutes, now full of bandits and soldiers eager to become rich through plunder and mischief.
The Yemenites took a neutral stance, sending emissaries to the Khan, hoping to be on good terms with the Mongolian overlord while not engaging in a war that wasn't profitable. On the other hand, the Egyptian sultan was delighted by the prospect of weakened Crusader States, invading Damietta and Sinai in 1247.
The garrisons of these weak states couldn't hold back the Egyptian army for more than three months, despite Egypt still being weakened and impoverished after being defeated by the crusader states and the Fatimid implosion. During the siege of Damietta the Egyptians used everything mean and tactic they could to break the unyielding defenders, Damietta was a location of high strategic import since the city controls access to the Nile and since its fall to the crusader's hands, the Egyptian economy and territorial integrity was endangered, only protected by the truces and other events that distracted the Christians.
A Venetian merchant named Gianluca di Bianchi, personal friend, counselor, and supporter of the Egyptian sultan and enemy to the count of Damietta used his vast network of spies and saboteurs to bribe some of the defenders to let them in during the darkest hour of the night, this led to a swift victory of the Ziyalid armies since the defenders weren't expecting a betrayal, at least 5,000 persons died during the siege. He was excommunicated, his assets confiscated, his honors stricken and completely despised. No one knows the motives behind his action course.
Nevertheless, after Damietta was conquered the crusader army was destroyed in Nuweiba, then El Tor and El Arish, the county of Sinai was the poorest and weakest of them all, and it fell definitely in 1249.
The Mongolians continued with their unstoppable advance, taking Edessa in 1246 and most of the surrounding area, Mosul was the next big objective, this being in Mahometan Mesopotamia, this siege, however, was cruel and unusually large, and grueling for both of the involved, it lasted from 1246 to 1254, almost 45,000 Mongol and vassal states troops died in this staggering siege, slowing severely the Mongol advance, while the city lost sixty percent of its population, Hulagu Khan, Baiju Noyan and Ariq Böke we're the principal leaders of the Mongolian army.
Ariq was the leader of the Syrian campaign, Baiju Noyan aimed for the kingdom of Jerusalem and Hulagu Khan along with Kitbuqa Noyan and the vassal kings of Georgia and Armenia, among others, invaded Mesopotamia.
Baiju, after taking Edessa, continued its march to Damascus, he was constantly attacked by Kurdish and Greek mercenaries, Assyrian auxiliaries, and the armies of the Duke, armies that grew in number with volunteers from all over the Christendom.
He besieged Raqqa and Aleppo, trying to deal a fatal blow to Syria, Raqqa fell in 1248, but Aleppo endured two more years until the walls crumbled after an earthquake and the city turned into a chaotic nightmare after a huge fire broke out, Hama, Salamiyah and Al-Suqaylabiyah fell few months later, leaving a free way to Homs, plunders, rapes and general abuses were common. Ariq was confident that his victory would be total and the Syrians and Jerusalemites alike would kneel and bow before the Khan once Homs was razed and Damascus was conquered, but he was so wrong, the Syrians mustered a massive army, more than a hundred thousand men, eager to kill the invaders and secure a better tomorrow for their families. The battle took place in the fifteenth day of September of 1251.
The battle that ensued is wrapped in mysticism and legend, some accountants claimed that the earth itself convulsed and opened its maws, swallowing the invaders, while an earthquake is present in both accounts, there is almost no proof of the earth devouring the Mongol army. What's real is that the horses of the Mongolians died or fell to the ground during the charge, this was caused by poisoning, duty carried by an unknown group, possibly a soldier from one of the client states.
Ariq and Baiju Noyan, who needed a safe pace to Jerusalem, were present, the battle went horribly for the Mongols, their weapons broke, their arrows didn't fly towards it target neither dealt great damage to them and Ariq's overconfident behavior proved to be one of the factors that led his men to an early grave beside sabotage. Ariq was vanquished by Prince Philip Plantagenet, the grandson of Richard Lionheart, who took his head as trophy, after a severe battering Baiju managed to retreat safely, while a good chunk of his army stayed behind to avoid attacks from the rear and further demoralization, he managed to flee in an orderly way instead of routing.
He retreated to Aleppo, calling reinforcements from the Turkish Bey, Ertrugul, he marched to Syria with an army of 34,000 men, as a way to demonstrate his fealty to the Great Khan, despite being Christian himself.
In Mesopotamia, however, the war went satisfactorily for the Mongols, by 1258 Baghdad, the wealthy, magnificent, and great city was in the grasp of the Mongols, Sultan Turanshah remained in the city, hoping for a great victory that would make the barbarians flee and be broke by his might, but that didn't happen, he merely had 50,000 thousand men, while the Mongolian one was at least three times its size.
After resisting heroically for thirteen days, Baghdad fell on the tenth day of February of 1258, Baghdad was sacked, the centers of learning and library were burnt down, the city was ravaged, set on fire and its inhabitants slaughtered, the once center of the Islamic world was now a ruin, unrecognizable from its glories of yore, Turanshah was slain and his family fled, that day, Baghdad was no more than ash and ruins, a shade of her former glory...