"Biography of Yunnan, Nanyue, Dongyue and Korea", Historical Records of the Former Han period. Published in the Qing period.
During his stay in Daxia, Zhang Qian saw bamboo canes from Qiong and silk cloth from Shu (both in present-day Sichuan Province). When he asked where these goods had come from, he was told that they had been brought by Bactrian merchants who had gotten them from India. From this, he concluded that India was not very far from Shu. He consequently suggested to Emperor Wu that it would be the only way going to Xi Nan rather than Shu without being menaced by the Qiang and the Xiongnu if he went southwest to serve Daxia. [Read more..]