The general Zhang Qian was sent by Emperor Wudi of the Han Dynasty (206 BC- AD 220) to recruit the Yuezhi, who were the enemies of the Xiongnu in the second century BC. As Yuezhi tribe, Xiongnu was also a nomadic group who attempted to invade the Kansu province of Han Dynasty. Because the Xiongnu could not be restrained with any lasting effects, Emperor Wu decided to look for an alliance with Yuezhi who had been defeated by their enemies Xiongnu and driven to the Ili valley, the western fringes of the Taklamakan Desert. As a result, general Zhang Qian with a caravan of 100 men set out the first travel from Chang'an, the capital of Han Dynasty, to the far West of the area beyond the Great Wall.