On 8 November 1256,
Hulegu Khan set up camp on a hilltop facing
Maymun-Diz and encircled the fortress with his forces by marching over the Alamut mountains via the
Taleqan valley and appearing at the foot of Maymun-Diz. Maymun-Diz could have been attacked by mangonels; that was not the case with
Alamut,
Nevisar Shah,
Lambsar and
Gerdkuh, all of which were on top of high peaks. Nevertheless, the strength of the fortification impressed the Mongols, who surveyed it from various angles to find a weak point. Since the winter was approaching, Hülegü was advised by the majority of his lieutenants to postpone the siege, but he decided to proceed. Preliminary bombardments were performed for three days by mangonels from a nearby hilltop with casualties on both sides. A direct Mongol assault on the fourth day was repulsed. The Mongols then used heavier siege engines hurling javelins dipped in burning pitch and set up additional mangonels all around the fortifications. An inexplicable aspect of the events for historians is why Alamut made no effort to assist their besieged comrades in Maymun-Diz. Khurshah instructed all Nizari castles of the Rusbar valley to capitulate, evacuate, and dismantle their forts. All castles (around forty) subsequently capitulated, except
Alamut (under
sipahsalar Muqaddam al-Din Muhammad Mubariz) and
Lambsar, possibly because their commanders thought the Imam had issued orders under duress and was practicing a sort of
taqiyya. Despite the small size of the fortress and its garrison, Alamut was stone-built (unlike Maymun-Diz), well-provisioned, and featured a reliable water supply. However, the Nizari faith demands the faithful pay absolute obedience to the
Imam in all circumstances. Hülegü surrounded Alamut with his army, and Khurshah unsuccessfully attempted to persuade its commander to surrender. Hülegü left a large force under Balaghai to besiege Alamut, and himself together with Khurshah set out to besiege the nearby Lambsar. == Siege ==