Muhammad II of Khwarezm

Muhammad II ruled the largest empire in the Islamic world and lost all of it to the Mongols in about two years, having provoked the invasion himself. He inherited Khwarezm in 1200 and expanded it enormously: he destroyed the Ghurids, took Transoxiana from the Qara Khitai, absorbed most of Persia, and by 1217 was marching on Baghdad to depose the caliph, having had himself proclaimed the rightful protector of Islam. The empire ran from the Indus to Anatolia. It was also new, administratively thin, garrisoned largely by Turkic troops loyal to his mother Terken Khatun rather than to him, and hated in the Persian cities it had recently conquered. Genghis Khan opened relations by sending a trade caravan of some four hundred and fifty merchants. The governor of Otrar seized it, accused the merchants of spying, and killed them; when Genghis sent envoys to demand redress, Muhammad had the leader executed and the others' beards burned off. The Mongol armies crossed in 1219. Rather than concentrate his forces he dispersed them among the walled cities, which allowed the Mongols to reduce them one at a time - Otrar, Bukhara, Samarkand, Urgench, Merv, Nishapur - with massacres calculated to make each subsequent siege shorter. Muhammad did not fight a pitched battle. He fled west with a Mongol column under Jebe and Subutai hunting him across Persia, and died of pleurisy in December 1220 on an island in the Caspian, reportedly in borrowed clothes with no attendants left. His son Jalal ad-Din fought on for a decade with real skill and no base. The cities did not recover for centuries.

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