The first time Zhang Qian to the Western Regions
After the Han Dynasty (206 BC – 220 AD) was established with the capital of Chang'an (now Xian) in 202 BC, the Han took the policy of intermarriage with the Huns in order to keep the peace along the northern border. In 141 BC, the ambitious Han Emperor Wudi (Liu Che) succeeded to the throne and wanted to defeat the Huns, because the Han Dynasty had become stronger during the reigns of his predecessors, Wendi (Liu Heng) and Jingdi (Liu Qi).In 139 BC, with the task of making a military alliance with the Da Yuezhi against the Huns, Zhang Qian was dispatched to the Western Regions by Wudi. Unfortunately, when he reached Hexi Corridor, he was captured by the Huns and was detained as a hostage for about ten years until he finally found a chance to flee. By way of Cheshi (Turpan Basin), Yanqi (Qarashar), he headed west along the Tarim River, passed through Qiuci (Kuche) and Shule (Kashgar), crossed the Pamirs and finally reached Da Yuezhi (in Amu Darya) via Dawan (in Fergana Basin) and Kangju (Between Balkhash and Aral Sea). However, the Da Yuezhi people were satisfied with their life and refused Zhang Qian's suggestion of an alliance. After investigating Daxia (Balkh) for about one year, he decided to return to Chang'an in 128 BC. In order to avoid the area controlled by Huns, he went over Pamirs, skirted the northern foot of the Kunlun Mountains, by way of Shache (Yarkand), Yutian (Khotan) and Shanshan (Ruoqiang) and reached the residence area of Qiang Minority. He was captured by the Huns again and was detained for one year. In 126 BC, he escaped and arrived in Chang'an. Wudi was very interested in the information that Zhang Qian brought about the vast Western Regions, especially about the swift horses in Dawan.
The second time Zhang Qian to the Western Regions
In 119 BC, Zhang Qian set out on his second journey to the Western Regions to ally with Wusun (in Ili River). To his surprise, Wusun didn't want to fight against the Huns. At the same, Zhang Qian sent deputy envoys to other states. They left their traces in Central Asia, Southwest Asia, even the Roman Empire around the Mediterranean and North Africa. Zhang Qian was the pioneer of the Silk Road, opening up the Southern Route and Central Route.