The Battle of Qatwan (1141)

After the fall of the Liao state in northern China, some of the Khitans came west under Yelü Dashi, took Balasagun and founded the Qara Khitai state. In 1137 they defeated the Western Karakhanids, vassals of the Seljuks, near Khujand, and the Karakhanid ruler appealed to Sultan Sanjar.

In 1141 Sanjar arrived in Samarkand with a large army. The Qara Khitai were helped by the Karluks, who were at odds with the Karakhanids and the Seljuks. On 9 September 1141, on the Qatwan steppe north of Samarkand, the Qara Khitai surrounded the Seljuk army and drove it into a dry valley called Dargham. The army was destroyed and Sanjar barely escaped.

After Qatwan Transoxiana passed to the Qara Khitai and Seljuk prestige in the east was shaken. The news even reached Europe, where Crusaders linked it to the legend of Prester John, a Christian king who had defeated the Muslims from the east.