Mingan took possession of the imperial treasury, where he found great stores of silk, and also of gold and silver plate. All these things he sent to Genghis Khan, who remained still at the north at a grand encampment which he had made in Tartary. After this, other campaigns were fought by Genghis Khan in China, in the course of which he extended his conquests still farther to the southward, and made himself master of a very great extent of country. After confirming these conquests, he selected from among such Chinese officers as were disposed to enter into his service suitable persons to be appointed governors of the provinces, and in this way annexed them to his dominions; these officers thus transferring their allegiance from the emperor to him, and covenanting to send to him the tribute which they should annually collect from their respective dominions. Every thing being thus settled in this quarter, Genghis Khan next turned his attention to the western frontiers of his empire, where the Tartar and Mongul territory bordered on Turkestan and the dominions of the Mohammedans. CHAPTER XVII. THE SULTAN MOHAMMED. 1217 Mohammedan countries on the west.--Sultan Mohammed.--Karazm.--Proposed embassy.--Makinut and his suite.--Speech of the embassador.--Father and son.--The sultan not pleased.--Private interview.--Anger of the sultan.--Conversation.--Makinut returns a soft answer.--The sultan is appeased.--Treaty made.--Genghis Khan is pleased.--Opening of the trade.--The exorbitant merchants.--Their punishment.--The next company.--Their artful management.--Genghis Khan fits out a company.--Embassadors.--Mohammedans.--Messengers from the court.--Large party.--Roads doubly guarded.--The Calif of Bagdad.--Mohammed's demand and the calif's reply.--The sultan calls a council.--Mohammed's plan for revenge.--March of the army.--Failure.--The calif's plans.--Objections to them.--Arguments of the calif.--Message to Genghis Khan.--Artful device.--The answer of Genghis Khan.--The caravan arrives at Otrar.--The governor's treachery.--The party massacred.--Genghis Khan hears the tidings.--He declares war.--Preparations. The portion of China which Genghis Khan had added to his dominions by the conquests described in the last chapter was called Katay, and the possession of it, added to the extensive territories which were previously under his sway, made his empire very vast. The country which he now held, either under his direct government, or as tributary provinces and kingdoms, extended north and south through the whole interior of Asia, and from the shores of the Japan and China Seas on the east, nearly to the Caspian Sea on the west, a distance of nearly three thousand miles.