Khwarazmian Dynasty

Also known as Khwarezmian Empire, Khwarezmshahs

Persianate Sunni empire of Central Asia that touched Crusader history twice — through the destruction of the Seljuk world in the early 13th century and through the Khwarazmian remnants who sacked Jerusalem and crushed the Frankish army at La Forbie in 1244.

The Khwarazmshahs were originally a Turkic governor's dynasty in Khwarezm under the late Seljuks. Through the late twelfth century they expanded into a major Persianate empire ruling Iran, Khorasan, and Transoxiana — and at their peak under 'Ala ad-Din Muhammad II (r. 1200–20) they formally extinguished the Great Seljuks of Persia and stretched from the Aral Sea to the Persian Gulf.

Their independent existence ended catastrophically in 1219–21 when an embassy dispute with the new Mongol confederation under Genghis Khan provoked the Mongol invasion of Central Asia. The Khwarazmian empire was annihilated in two seasons: Bukhara, Samarqand, Merv, Nishapur, and the Khwarazmian heartland were sacked in turn, and the last Khwarazmshah Jalal ad-Din died fugitive in the Kurdish mountains in 1231.

Their relevance to Crusader history is concentrated in a single year. In 1244 a band of Khwarazmian cavalry — landless mercenaries left over from the wreck of their state, hired by the Ayyubid sultan al-Salih Ayyub of Egypt — broke into the kingdom of Jerusalem, sacked the Holy City on 11 July, and on 17–18 October destroyed the joint Frankish-Damascene field army at La Forbie outside Gaza. La Forbie was the most damaging Frankish defeat since Hattin and is conventionally taken as the moment the kingdom of Jerusalem became militarily unrecoverable.

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