The first act of this new ruler was to order his subjects to observe every practice of Islam, and next he took measures to suppress robbery and murder. But only one year had passed when the Mongol tempest came. Though Rokn ud din and the Ismailians could not foresee it the doom of Alamut and all who belonged to it had been settled. The Grand Khan had instructed Hulagu to destroy them, and the master of Persia was advancing to the execution. Rokn ud din sent an officer to Yassaur, at Hamadan to assure him of his submission to the Mongol Empire. This general advised him to visit Prince Hulagu, who had just come to Persia. Rokn ud din, alarmed for his own safety, answered that he would send his brother, Shahinshah, in advance. Yassaur consented to this and charged his own son to go with Shahinshah. But meanwhile he entered the Alamut region with an army corps of Persians and Turks, and attacked that great fortress June, 1256. After a sharp struggle his men were forced back, and out of revenge he destroyed all the harvest, and ravaged the country. Hulagu had commissioned Guga Ilga and Kita Buga to finish the conquest of Kuhistan which the latter had begun two years earlier. He had made rather slow progress alone, but aided by Guga Ilga he captured Tun and slew all the people, excepting young women and children. This done both commanders joined Hulagu. After Hulagu had received Shahinshah at headquarters he sent Rokn ud din this message: “Since thou hast sent thy brother with expressions of submission we will forgive the crimes committed by thy father. Raze thy castles and come to our camp. No harm will be done to the country.” When Rokn ud din had demolished several castles and dismounted the Alamut gates with those of Meimundiz and Lemsher, Yassaur left Ismailian territory. But Rokn ud din, while giving assurances of obedience, and receiving a Mongol governor, asked the term of one year in which to do homage to Hulagu. Hulagu sent envoys a second time to induce the Alamut ruler, through promises and threats, to visit him. When these envoys were returning Rokn ud din sent with them a cousin of his father, and his own vizir Shems ud din Kileki, who were to present his excuses and obtain the delay which he asked for. He begged also to retain the three castles, Alamut, Lemsher and Lal, engaging in this case to surrender all others. He hoped by this yielding to win the delay which he needed. He was merely waiting for winter, which would stop every action in that entire mountain region. The only answer given by Hulagu, who had just captured the castle of Shahdiz, was a summons to his camp pitched at that time near Demavend. He added that if Rokn ud din needed a few days to bring his affairs into order he might have them, but he must send his son straightway.