Zhang Qian travels to the Western Regions
In the early years of Emperor Wu of Han, some members of the Xiongnu surrendered to the Han Dynasty. Emperor Wu of Han learned a little about the situation in the Western Regions (now Xinjiang and the area west of Xinjiang) from their conversation. They said there was a Yue clan (pronounced yu è - zh ī) that was defeated by the Xiongnu and fled westward, settling in the Western Regions. They have a grudge against the Xiongnu and want revenge, but no one helps them.
Emperor Wu of Han thought that since the Yue clan was located to the west of the Xiongnu. If the Han Dynasty could unite with the Yue clan and cut off the connection between the Xiongnu and the Western Regions, wouldn't that be equivalent to cutting off the Xiongnu's right arm?
So he issued a decree, soliciting capable people to contact the Yue clan. Prior to this, no one knew where the Yueshi Kingdom was or how far it was. To fulfill this obligation, one must have great courage.
There was a young Langzhong (official name) named Zhang Qian (pronounced qi ā n) who thought it was a meaningful thing and first applied. With him leading the way, others became bolder, and a hundred brave warriors responded to the expedition. There is a Xiongnu man named Tangyifu in Chang'an who is also willing to go with Zhang Qian to find the Yue Kingdom.
In 138 BC, Emperor Wu of Han sent Zhang Qian with over a hundred people to set out in search of the Yue clan. But to reach the Moon Clan, one must pass through the territory occupied by the Xiongnu. Zhang Qian and his companions walked carefully for a few days, but were still found and surrounded by Xiongnu soldiers, all of whom were captured.
The Xiongnu did not kill them, but sent people to gather and manage them. Only Tangyi Father and Zhang Qian lived together for more than ten years.
Over time, the Xiongnu have become less strict with them. Zhang Qian discussed with his father in Tangyi and saw that the Xiongnu were unprepared, so they rode two fast horses and escaped.
They had been running westward for dozens of days, enduring hardships and escaping from the territory of the Xiongnu. They couldn't find the Yue clan, but instead broke into another country called Dawan (in present-day Central Asia).
Dawan and the Xiongnu are close neighbors, and the locals understand the Xiongnu language. Zhang Qian and Tang Yifu can both speak Xiongnu dialect, making it very convenient to talk. They met the King of Dawan, who had long heard that the Han Dynasty was a prosperous and powerful country. This time, when he heard that the Han Dynasty's envoy had arrived, he received them very well and sent someone to escort them to Kangju (about between Lake Balkhash and the Salt Sea today), and then from Kangju to the Yue clan.
After being defeated by the Xiongnu, the Yue clan moved to the vicinity of Daxia (now northern Afghanistan) and established the Dayue clan state, no longer wanting to fight against the Xiongnu. The King of Dayue was not interested in hearing Zhang Qian's words, but because Zhang Qian was an envoy of the Han Dynasty, he received him very politely.
Zhang Qian and his cousin's father lived in the Dayue family for over a year and even went to Daxia once, where they saw many things they had never seen before. But they were unable to persuade the Dayue Kingdom to jointly deal with the Xiongnu, so they had to return. After passing through the territory of the Xiongnu, he was detained for a period of time. Fortunately, the Xiongnu experienced internal strife and managed to escape and travel back and forth to Chang'an.
Zhang Qian stayed outside for thirteen years before returning. Emperor Wu of Han believed that he had made great contributions and appointed him as the Grand Tutor.