Mongol Invasion of Khwarezmia

The Mongol invasion 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 Eurasia, save for Western Europe, Fennoscandia, the Byzantine Empire, Arabia, Indian subcontinent, Japan and parts of Southeast Asia.

Incidentally, 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." 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. Even his invasions of China, to that point, had involved no more bloodshed than previous nomadic invasions had caused. 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 utterly destroyed.