Mongol Conquest of Khorasan

Timeline

1. 1220Northern Khorasan · KhorasanAfter Samarkand fell, Genghis Khan ordered his youngest son Tolui to lead the main force south to conquer Khorasan. Tolui's army advanced from Central Asia, forcing the surrender or capturing numerous towns along the way, and northern Khorasan quickly fell under Mongol control.
2. 1220–1221Merv and Nishapur · KhorasanTolui's army successively captured Merv and Nishapur. Merv suffered a massive massacre on its fall, its population nearly exterminated; the garrison of Nishapur resisted and retook the city several times before it was utterly destroyed in April 1221. Both cities were Khorasan's most important cultural and commercial centers.
3. 1220Western Khorasan and Tus · KhorasanJebe and Subutai, in pursuit of the shah, swept through western Khorasan, capturing Tus, Damghan, and other cities. Their high-speed pursuit left local garrisons no time to organize defenses, and the western Khorasan corridor rapidly came under Mongol control.
4. 1221Khorasan · KhorasanBy 1221, Khorasan's major cities had all fallen, and the Mongols established rule over the region, collecting taxes and stationing garrisons. The once-prosperous Khorasan urban belt suffered devastating blows, and its population and handicrafts never recovered to pre-war levels for a long time.