Some sources say the Ismaili-Hashashin's imam Alaud-Din dispatched hundreds of assassins to kill Möngke in his palace. Shams-ud-Din, the chief judge of Qazvin, had denounced the menace of the Ismailis. Hence, Möngke decided to exterminate the sect. Möngke ordered the Jochid and Chagataid families to join Hulagu's expedition to Iran and strengthened the army with 1,000 siege engineers from China. Möngke's armies, led by his brother Hulagu, launched an attack on the Ismailis in Iran, crushing the last major resistance there by the end of 1256. The Hashashin Imam Rukn ad-Din requested permission to travel to Karakorum to meet with the Great Khan Möngke himself. Hulagu sent him on the long journey to Mongolia, but once the Imam arrived there, Möngke criticized his action and dismissed him. Rukn ad-Din was killed in uncertain circumstances. For the Abbasids, envoys from Baghdad attended the coronation of Möngke in 1251 to come to terms with the Mongols. However, Möngke told Hulagu that if the Caliph Al-Musta'sim refused to meet him in person, then Hulagu was to destroy Baghdad. Hulagu then advanced on Iraq, taking the capital at Baghdad in 1258. Hulagu sent Möngke some of his war booty with the news of his conquest of Baghdad. Möngke dispatched a Chinese messenger to congratulate him for his victory. Outraged by the attack on the caliphate, Malik Kamil revolted, killing his Mongol overseer. Hulagu's son Yoshumut invested Mayyafariqin and executed Malik Kamil. From there they moved into Syria in 1259, took Damascus and Aleppo, and reached the shores of the Mediterranean. Fearing the Mongol advance, the Ayyubid Sultan Malik Nasir Yusuf refused to see Hulagu and fled. However, the Mongols captured him at Gaza. In 1241 Töregene Khatun had sent an envoy to make peace proposals and discuss with Zhao Yun (posthumously known as Emperor Lizong). The Song court arrested the envoy and imprisoned him in a fortress with his suite of seventy persons. The envoy died, but his suite were detained until 1254. That year the Mongol army attacked to take Hejiu but failed.