Trying to maintain diplomacy, Genghis sent an envoy of three men to the Shah, to give him a chance to disclaim all knowledge of the governor's actions and hand him over to the Mongols for punishment. The shah executed the envoy (again, some sources claim one man was executed, some claim all three were), and then immediately had the Mongol merchant party (Muslim and Mongol alike) put to death. These events led Genghis to retaliate with a force of 100,000 to 150,000 men that crossed the Jaxartes in 1219 and sacked the cities of Samarkand, Bukhara, Otrar and others. Muhammad's capital city, Urgench, followed soon after.