Yelü Dashi founds the Qara Khitai (Western Liao)

Yelü Dashi, a member of the Liao imperial clan who in 1115 had passed the highest civil-service examination, served the dynasty as a provincial governor during its war with the Jurchens. In 1124, as the Jin overran the Liao, he broke with Emperor Tianzuo — whom the Jin captured the following year — and led a band of officials and soldiers to the garrison town of Kedun on the Orkhon, where its 20,000 troops accepted his leadership. Accounts differ on when he took the title of gurkhan, ‘universal khan’: some place it at Kedun in 1124, others in 1132, when he was enthroned as emperor.

In 1130 (by some accounts 1129) he moved west and set up a base on the Emil River, near today’s border between China and Kazakhstan; an attack on Kashgar in 1131 failed. In 1134 Ibrahim II, the Eastern Karakhanid ruler of Balasagun, asked for his help against the Karluks and Kangli; Yelü Dashi came, deposed him and made Balasagun his capital, and the Kangli, the Karluks, the Kyrgyz and the Uyghur kingdom of Qocho became his vassals. His attempt to win back northern China from the Jin failed, but in May 1137 he defeated the Western Karakhanids at Khujand and annexed Fergana and Tashkent; in 1141 he crushed the Seljuk sultan Sanjar at Qatwan, and from 1142 Khwarazm paid him a yearly tribute of 30,000 dinars.

Yelü Dashi died in 1143, and his empress Xiao Tabuyan ruled as regent. The Khitan rulers of the Qara Khitai, who followed Buddhism and their own traditional religion, governed a mostly Muslim population — with Buddhist and Nestorian minorities — largely through vassal dynasties, keeping the Chinese calendar and Chinese imperial and administrative titles. The empire lasted until the Naiman prince Kuchlug usurped power in 1211; in 1218 it fell to the Mongols.