The Mongol army marched now against Herat, the last city left in Khorassan. The governor, who had slain the envoy sent by Tului to summon the place to surrender, exhorted all men to fight desperately, to fight to the death. The struggle continued eight days, and Herat fought with immense resolution and fury; on that day the governor fell, and a small party sprang up which declared for submission. Tului knowing this state of mind in the city, promised to spare the people, if they would submit to him straightway. The offer was accepted. He spared all the citizens, excepting twelve thousand devoted to Jelal ud din, the new sovereign, and appointed a Mohammedan governor, with a Mongol commandant to help him. Eight days later Tului received from Talekan a command to go to his father. While Tului was ruining Khorassan, a small group of Turkmans, Khankalis, who were living near Merv, fearing the Mongols, moved westward, and after some wandering in Asia Minor, settled at last near Angora under Ertogrul their tribe chieftain. They numbered in those days four hundred and forty families. These Turkmans formed the nucleus of the Ottoman Empire, so famous in history until our day. After he had destroyed Talekan, Jinghis held his summer camp for a time in the neighboring mountains. His sons, Jagatai and Ogotai, returned from Urgendj and other ruined places on the Oxus. Juchi went north of Lake Aral and in deep and unquenchable anger began to establish the monarchy of Kipchak, known later as the Golden Horde, and never again saw his father. Jinghis learning, toward the autumn of 1221, that Jelal ud din had large forces in Ghazni, directed his march toward that city to crush him. The great Khan was detained a whole month at Kerduan, a firm fortress, but he destroyed it at last, with all its defenders. He crossed the Hindu Kush after that and besieged Bamian, where he lost one grandson stricken dead by an arrow; this was Moatagan, son of Jagatai. To avenge this death Bamian was stormed promptly, and taken. Jinghis would not have it in another way. The command was given to leave nothing alive, and take no booty of any kind. Every living creature had to die, and every thing of value was broken or burned. Bamian was renamed Mobalig (the city of woe), and the region about it was turned to a desert. A hundred years later it contained no inhabitants. Just after this destruction came the news of Jelal ud din’s victory over a Mongol division, commanded by Kutuku, who had been protecting the Khan’s operations and those of Tului on the south side. This victory was gained at Peruan, not far from the Bamian boundary. It brought more harm to the victor, however, than profit, for it caused a sudden rupture between his commanders, some of whom deserted and led away many warriors. With reduced ranks he was forced to fall back upon Ghazni, and thence farther south when he heard that Jinghis was advancing rapidly to avenge the defeat of Kutuku, his general.