Mongol campaign against the Nizaris participant Golden Horde
Campaign against Rudbar and Alamut
As soon as he had been in power, Khurshah announced the Nizari leadership's willingness to submit to the Mongol rule to the nearest Mongol commander, noyan Yasur in Qazvin. Yasur replied that the Imam personally should visit Hülegü's camp. Fightings are recorded between Yasur and the Nizaris of Rudbar: on June 12, he was defeated in a battle on Mount Siyalan near Alamut, where the Nizari forces had been mustered, but managed to harass the Nizaris of the region.As Hülegü reached Bistam, his army had enlarged into five tümens, and new commanders were added. Many of them were the relatives of Batu Khan. From the ulus of Jochi representing the Golden Horde came Quli (son of Orda), Balagha, and Tutar. Chagatai Khanate forces were under Tegüder. A contingent of Oirat tribesmen also joined under Buqa Temür. No member of Ögedei's family is mentioned. Hülegü had with him a thousand squads of siege engineers (probably north Chinese, Khitan and Muslim) skilled in the use of mangonels and naphtha.
The Mongols campaigned against the Nizari heartland of Alamut and Rudbar from three directions. The right wing, under Buqa Temür and Köke Ilgei, marched via Tabaristan. The left wing, under Tegüder and Kitbuqa, marched via Khuwar and Semnan. The center was under Hulegu himself. Meanwhile, Hülegü sent another warning to Khurshah. Khurshah was in Maymun-Diz fortress and was apparently playing for time; by resisting longer, the arrival of winter could have stopped the Mongol campaigning. He sent his vizier Kayqubad; they met the Mongols in Firuzkuh and offered the surrender of all strongholds except Alamut and Lambsar, and again asked for a year's delay for Khurshah to visit Hülegü in person. Meanwhile, Khurshah ordered Gerdkuh and fortresses of Quhistan to surrender, which their chiefs did, but the garrison of Gerdkuh continued to resist. The Mongols continued to advance and reached Lar, Damavand, and Shahdiz. Khurshah sent his 7- or 8-years-old son as a show of good faith, but he was sent back due to his young age. Khurshah then sent his second brother Shahanshah (Shahin Shah), who met the Mongols at Rey. But Hülegü demanded the dismantling of the Nizari fortifications to show his goodwill.Numerous negotiations between the Nizari Imam and Hülegü were futile. Apparently, the Nizari Imam sought to at least keep the main Nizari strongholds, while the Mongols were adamant that the Nizaris must fully submit.