 It was an important site along the Silk Road trade route leading west, and was adjacent to the Korla and Karasahr kingdoms to the west.From 450 AD until 640 AD it became Jiao prefecture in the Tang Dynasty, and in 640 AD it was made the seat of the new Jiaohe County.From 640 AD until 658 AD it was also the seat of the Protector General of the Western Regions, the highest level military post of a Chinese military commander posted in the west.