A mamluk shahdom fell to Genghis in two catastrophic years
Khwarazm was a Persianate Sunni empire of Turkic mamluk stock under the Anushtegin line, holding swathes of Central Asia, Afghanistan, and Iran from 1077 to 1231. At its widest it may have covered 2.3 to 3.6 million square kilometres—until Genghis Khan’s 1219 onslaught overran it in roughly two years.
The title long predated the empire. Khwarazmshah was created in 305 by the founder of the Afrighid line and lasted until 995, then returned after a gap. In 1017 rebels murdered Khwarazmshah Ma'mun II and his wife, a sister of Mahmud of Ghazni, and Mahmud invaded, installed his own man and made the region a Ghaznavid province until 1035.
The dynasty that built the empire began with a slave. Anush Tigin Gharchai started as a Turkic slave of the rulers of Gharchistan and became a Seljuk mamluk. In 1073 Sultan Malik-Shah I sent him with his master to win back northern Khorasan from the Ghaznavids, then made him keeper of the royal vessels; Khwarazm's revenues funded that office, so he became its governor, from about 1077 until his death by 1097. A local governor, Ekinchi, briefly declared himself shah and was killed, and the Seljuks installed Anush Tigin's son Qutb al-Din Muhammad, the first hereditary Khwarazmshah.
Real independence came under Ala ad-Din Atsiz, who ruled from 1127 to 1156. He rebelled against Sultan Sanjar in 1138, lost at Hazarasp and fled, came back and pushed out Sanjar's nephew, then submitted again by 1141 and was pardoned. When the Qara Khitai crushed the Seljuks at Qatwan that year, Atsiz seized Merv and Nishapur, though Qara Khitai raids forced him to pay them tribute. The shahs served the Seljuks and then the Qara Khitai as vassals until about 1190.
At its peak Khwarazm was the strongest power in and around Persia, having beaten the Seljuks and Ghurids and menaced the Abbasid caliph, with estimates of its area ranging between 2.3 and 3.6 million km². It copied Seljuk government and relied on a vast cavalry drawn mostly from Kipchak Turks. None of it held when Genghis Khan invaded in 1219. Exploiting internal rifts, the Mongols took most of the empire within two years, sacking its richest cities and slaughtering their people in one of history's bloodiest conquests. A rump state in western Iran held out until 1231, falling only once Jalal al-Din Mangburni, the final shah, had died.
Source: Khwarazmian Empire
