Yalavach quelled his anger and made him agree to establish friendly relations with Genghis Khan. In this way, the first ambassador of the Sultan Muhammad was accepted in Beijing, and Genghis declared trade between the Mongols and Khwarazmians as a necessity for establishing friendly relations. During this situation, a number of Muslim merchants from Sultan Muhammad's territory took some goods to the Mongol Empire, and although Genghis treated them violently at the beginning of their arrival, he finally appeased them and sent them back With respect. At the time that they were returning in 1218, a number of Mongol merchants, whose number reached 450 and apparently most of them were Muslims, was send by Genghis with some goods and a letter containing his advice and request to establish relations between the two governments. But Inalchuq, the ruler of Otrar who was the nephew of the Terken Khatun (Sultan Muhammad's mother) and supported by her, was greedy for the wealth of the merchants and arrested the Mongol merchants on the charge of espionage on the border of the territory under his rule, and then with the permission of Sultan Muhammad, who was in the Persian Iraq at that time, massacred all these merchants. Then the officials of Khwarazmian sold the cargo of the caravan, which included 500 camels of gold, silver, Chinese silk artefacts, precious skins and such on, and sent the resulting amount to the capital of Khwarazmian government. When the news of Otrar incident reached Genghis Khan, Genghis Khan decided to control his anger and made his last attempt to gain satisfaction through diplomacy. He sent a Muslim, who was previously in the service of Sultan Tekish and was accompanied by two Mongols, to protest against the performance of Inalchuq and requested to surrender him the Mongols. Sultan Muhammad didn't want to surrender Inalchuq because most of the leaders of Khwarazmian army were his relatives, and also Terken Khatun who had influence in the Khwarazmian court was supporting him. Therefore, Sultan Muhammad not only didn't accept Genghis Khan's request, but also killed his Muslim envoy who came to Samarqand, the capital of Khwarezmian, and sent his companions back to Genghis with their beards and mustaches cut off. This bellicose behavior of Sultan accelerated Mongol invasion of Central Asia. Historians cite the fact that Genghis was already bogged down in his war against the Jin in China, and that he