It also established the Ili River as the border between the two states .
The Ili River treaty of 638 AD formalized the division of the Western Turkic Kaganate ( 552 -- 638 AD ) into the Nushibi and the Dulu .
Ili River also established the Ili River as the border between the two states .
The Ili River treaty of 638 AD formalized the division of the Western Turkic Kaganate ( 552 -- 638 AD ) into the Nushibi and the Dulu .