The Cambridge History of India, Vol. I: Ancient India v1.c31.18

v1.c31.18

Certain incidents in this migration, which must have extended over some thirty or forty years, are recorded by Chinese authors. In the country of the Ili river, now called Kulja, the Yueh-chi came upon a tribe called the Wu-sun. The Wu-sun were routed, and their king was slain; and the Yueh-chi continued their journey westwards towards the Issyk-kul Lake in the country which was until recently Russian Turkestān. Here they appear to have divided themselves into two bands—the one, afterwards known as the Little Yueh-chi, going southwards and settling on the borders of Tibet, and the other, the Great Yueh-chi, continuing their movement to the west until they came into contact with a people whom the Chinese called Sse (Saï) or Sek, and who are probably to be identified with the Çakas of the Jaxartes. The Yueh-chi took possession of the country of the Çakas; and the Çakas being driven to the south-west occupied the country of the Ta-hia or Bactria.