Claim: Genghis Khan controlled a significant territory.

The Mongol conquest of Khwarezmia from 1219 to 1221 marked the beginning of the Mongol conquest of the Islamic states . The Mongol expansion would ultimately culminate in the conquest of virtually all of Asia -LRB- as well as parts of Eastern Europe -RRB- save for Japan , the Mamluk Sultanate of Egypt and most of the Indian subcontinent and Southeast Asia .   It was not originally the intention of the Mongol Empire to invade the Khwarezmid Empire . According to the Persian historian Juzjani , Genghis Khan had originally sent the ruler of the Khwarezmid Empire , Ala ad-Din Muhammad , a message seeking trade and greeted him as his neighbor : `` I am master of the lands of the rising sun while you rule those of the setting sun . Let us conclude a firm treaty of friendship and peace . '' or he said `` I am Khan of the lands of the rising sun while you are sultan those of the setting sun : Let us conclude a firm agreement of friendship and peace . '' The Mongols ' original unification of all `` people in felt tents '' , unifying the nomadic tribes in Mongolia and then the Turcomens and other nomadic peoples , had come with relatively little bloodshed , and almost no material loss . The Mongol wars with the Jurchens however had shown how cruel the Mongols could be . Shah Muhammad reluctantly agreed to this peace treaty , but it was not to last . The war started less than a year later , when a Mongol caravan and its envoys were massacred in the Khwarezmian city of Otrar .   In the ensuing war , lasting less than two years , the Khwarezmid Empire was destroyed .