Yuezhi, and established a dominant confederacy empire during the Chu-Han contention and the early Han dynasty. Han dynasty During the reign of Emperor Wen of Han, Modu's son Laoshang Chanyu defeated Yuezhi again in 162 BCE, forcing the westward exodus of majority of the Yuezhi survivors (later known as the Greater Yuezhi) into Central Asia, while the small portion of Yuezhi population that didn't migrate (known as the Lesser Yuezhi) was forced to mixed among the Qiang people and become the subjects of Xiongnu's Worthy Prince of the Right. At this point, the Hexi Corridor was under complete Xiongnu control, mainly occupied by the two tribes of Hunye and Xiutu. In 138 BCE, Emperor Wu sent Zhang Qian as the ambassador to the Western Regions in an attempt to make contact with Greater Yuezhi. Zhang Qian's envoy was intercepted by Xiongnu while travelling through the Hexi Corridor, and he was held a captive for ten years, until he finally escaped and continued his mission further west. He eventually arrived at Yuezhi territory, but was unable to convince the Yuezhi leaders to ally against Xiongnu. On his return journey he was once again captured by Xiongnu while traversing the Hexi Corridor, but again managed to escape two years later. He finally returned to Chang'an in 125 BCE, bring back invaluable detailed information about the various Central Asian kingdoms such as Dayuan, Daxia and Kangju, as well as other farther countries such as Anxi, Tiaozhi, Shendu and Wusun. During the Han–Xiongnu War, Han general Huo Qubing expelled the Xiongnu from the Hexi Corridor and even drove them from Lop Nur when King Hunye surrendered to Huo Qubing in 121 BCE. The Han Empire acquired a new territory with trade access to the Western Regions, and also cutting the Xiongnu off from their Qiang allies. Again in 111 BCE, Han forces repelled a joint Xiongnu-Qiang invasion, and to consolidate the control of the region, four new commanderies were established in the Hexi Corridor, namely (from east to west) Wuwei, Zhangye, Jiuquan and Dunhuang, collectively known as the Four Commanderies of Hexi (). From roughly 115–60 BCE, Han forces fought the Xiongnu over control of the oasis city-states in the Tarim Basin. Han was eventually victorious and established the Protectorate of the Western Regions in 60 BCE, which dealt with the region's defense and foreign affairs. During the turbulent reign of Wang Mang, Han