Li Chong was the last protector of the Western Regions at the end of the Han Dynasty, serving from 16 BC to 23 BC.

Li Chong was the last protector of the Western Regions at the end of the Han Dynasty, serving from 16 BC to 23 BC
In the first year of the Western Han Dynasty (8 BC), Wang Mang accepted the title of emperor after receiving the infant Chan concession and changed the name of the country to Xin. After Wang Mang usurped the Han Dynasty, in order to promote the national prestige of the new dynasty, in the first year of the founding of the people (9 BC), all the kings of the Western Regions, including the Southern Xiongnu kings, were granted new seals, reducing the rank and status granted by the Han Dynasty to the kings of the Western Regions and the Xiongnu Shan Yu, and implementing ethnic inequality policies in the countries of the Western Regions, causing the Western Regions to be established. In particular, the Xiongnu's strong dissatisfaction with the new dynasty led to the intensification of contradictions between the western states and the new dynasty. After that, the Xiongnu power became increasingly rampant in the western region and openly confronted the new dynasty.
In the fifth year of the founding of the new dynasty (13 BC), the Yanqi state first defected to the Xiongnu to rebel against the new dynasty, and raised an army to attack Guizi, the seat of the Western Regions Capital. The Western Regions capital Danqin was killed by the Yanqi State, and Guizi was completely lost and blocked by the Silk Road.
The Western Regions capital Danqin was killed by the Yanqi State, and Guizi was completely lost
In the third year of the new Dynasty Tianfeng (16 BC), Wang Mang, after comprehensively analyzing the situation in the Western Regions, sent Li Chong to succeed Dan Qin as the Protector of the Western Regions, and went on a campaign to the Western Regions with the Han Wuwei general Wang Jun and Guo Qin, who was also a lieutenant of the Western Regions Capital Protectorate. When the Han army arrived, all the countries in the western region surrendered to meet them, but the Yanqi state surrendered fraudulently, relying on the Xiongnu forces to gather troops to prepare themselves. After analyzing the situation, Li Chong and Wang Jun dispatched more than 7,000 soldiers and horses from the Guizi State, the Shache State, and the Gumo State to attack the Yanqi State. The expedition took Wang Jun as the vanguard, Li Chong's main force marched to Yanqi, and Guo Qin led his troops to reinforce.
Due to the misjudgment of the situation of the battle and the lag of Guo Qin's reinforcements, the battle ended in the disastrous defeat of Li Chong and Wang Jun. After Wang Jun led the soldiers and horses of the Guizi and Shache states to Yanqi, they were ambushed by Yanqi soldiers and horses, and the Han army was unfavorable, and Li Chong, who arrived later, also encountered strong resistance from Yanqi and Xiongnu soldiers.
Wang Jun led the soldiers and horses of the Guizi Kingdom and the Shache State to Yanqi
At this time, the soldiers and horses of the Gumo state who accompanied the battle rebelled, surrendered to the Yanqi state, and returned to launch a surprise attack on Wang Jun, and Wang Jun and his entire army were destroyed. Li Chong's main force fought hard, and the casualties were heavy, and after Guo Qin led the reinforcements to arrive, he knew that he was outnumbered, and when he saw the situation, he led his troops to break through, took the road of the car division, and broke through the Xiongnu blockade and returned to the interior. Li Chong, who broke out of the siege, gathered the remnants and retreated to Guizi, strangled the dangerous weigan river, and held out with the King of Guizi for 8 years, and died in the later battle.
After that, the new dynasty gradually lost its effective management of the western regions.
(References: Book of Han, A Brief History of Xinjiang, Outline of Xinjiang History)