Genghis Khan defeated the Kara-Khitai in 1218. The campaign brought the Mongol Empire into Central Asia and opened a direct frontier with the powerful Khwarazmian Empire.
The Kara-Khitai, also called the Qara Khitai or Western Liao, ruled a large Central Asian state. By the early thirteenth century, its government had been weakened by internal conflict and by the rise of Kuchlug, a Naiman prince who seized power. Kuchlug alienated much of the population, especially Muslim communities, through religious persecution and heavy-handed rule.
Genghis Khan sent the general Jebe west in 1218 with a force commonly estimated at about 20,000 troops. Jebe defeated Kuchlug’s forces near Balasagun, the Kara-Khitai capital. Kuchlug fled south but was eventually captured and executed by local hunters, who handed him over to the Mongols.
The conquest is often described as a 1218 victory, although the Mongols consolidated some former Kara-Khitai territories over the following years. This campaign also helped set the stage for the Mongol invasion of the Khwarazmian Empire beginning in 1219.