The sultan, however, did not seek shelter in this way for himself. He selected from his troops a certain portion of those who were most active and alert and were best mounted, and formed of them a sort of flying squadron with which he could move rapidly from place to place through the country, wherever his aid might be most required. Genghis Khan, of course, now prepared to attack the cities where the several divisions of the sultan's army had intrenched themselves. He wished first to get possession of Otrar, which was the place where the embassadors and the merchants had been massacred. But the city was not very large, and so, instead of marching toward it himself, he gave the charge of capturing it to two of his younger sons, whom he sent off for the purpose at the head of a suitable detachment. He himself, with the main body, set off upon a march toward the cities of Samarcand and Bokhara, which were the great central cities of the sultan's dominions. CHAPTER XIX. THE FALL OF BOKHARA. 1218-1219 Description of the town Bokhara.--Zarnuk.--An immediate surrender.--Nur.--Fate of Nur.--The siege of Bokhara commenced.--The sultan's anxiety.--Intercepted letters.--The deserter.--The outer wall taken.--Grand sortie made by the garrison.--Evacuation of the town.--Pursuit.--The fugitives overtaken.--Surrender.--Conditions made.--The governor of the citadel.--Genghis Khan enters the city.--Valuables surrendered.--The emperor in the mosque.--Desecration of the mosque.--Genghis Khan makes a speech.--The inhabitants give up every thing.--Conflagration.--Surrender of the citadel.--The town utterly destroyed.--News of the fall of Otrar.--Plans for the defense of Otrar.--Sorties.--The proposal made to Genghis Khan.--The siege renewed.--The outer walls taken.--Desperate conflicts.--Kariakas and the governor.--Treason.--Punishment of treason.--The Monguls enter the town.--Citadel stormed.--Desperation of the governor.--Courage and devotion of his wife.--The governor's fate. Bokhara was a great and beautiful city. It was situated in the midst of a very fine and fertile country, in a position very favorable for the trade and commerce of those days. It was also a great seat of learning and of the arts and sciences. It contained many institutions in which were taught such arts and sciences as were then cultivated, and students resorted to it from all the portions of Western Asia. The city proper was inclosed with a strong wall. Besides this there was an outer wall, thirty miles in circumference, which inclosed the suburbs of the town, and also a beautiful region of parks and gardens, which contained the public places of amusement and the villas of the wealthy inhabitants. It was this peaceful seat of industry and wealth that Genghis Khan, with his hordes of ruthless barbarians, was coming now to sack and plunder.