Changji Xinjiang Uygur Zizhiqu (Sinkiang) China

The Western Regions, or Xiyu, is a historical name specified in the Chinese chronicles between the third century BCE to eighth century CE that refers to the regions west of the Jade Gate (Yumen Pass), most often Central Asia or sometimes more specifically the easternmost portion of it (e.g., the Tarim Basin in southern Xinjiang).

Because of its strategic location astride the Silk Road, the Western Regions have been historically significant since at least the third century BCE.

The area until CE 89 is the scene of conflict between the Xiongnu and the Early and Later Han Dynasties.

The Xin dynasty’s troubles with the Xiyu kingdoms had begun in CE 10, when, Xuzhili, the King of Rear Cheshi (now part of Changji Hui Autonomous Prefecture) had grown concerned over the great cost of hosting Xin ambassadors, becoming so distressed that he considers abandoning his kingdom and fleeing to Xiongnu.

Xin's Xiyu commissioner Dan Qin summons Xuzhili and executes him.

Xuzhili's brother Hulanzhi flees to the Xiongnu and attacks Dan, inflicting severe casualties, before withdrawing.

Also in 13, perhaps related to the Wusun situation, the Xiyu kingdoms join forces, attack the Xiyu commissioner Dan, and succeed in killing him.

The Xiyu kingdoms by this point no longer pledge allegiance to the Xin dynasty.

Dou and Geng lead a major military expedition in 74 against a major remaining ally of the Northern Xiongnu, Cheshi (roughly modern Changji Hui Autonomous Prefecture, Xinjiang).

Cheshi submits, and at Dou's suggestion, the office of the Protector General of Xiyu is reinstituted.

Geng Gong, one of the deputies of the protector general, repels a Northern Xiongnu expedition in 75 to recapture Cheshi.