In the Han Dynasty，China established extensive contacts with various nationalities and kingdoms outside its domain through the Silk Road.Zhang Qian pioneered this route. During the reign of Emperor Wu，the Huns in the North often harassed the frontier of the Han Dynasty，and controlled dozens of small kingdoms in the Western Regions.

In 138 BC.，Emperor Wu sent Zhang Qian with a delegation of over 100 people on a diplomatic mission to the Western Re-gions to seek allies against the Huns.Zhang Qian was captured by the Huns just as he left the Han territory，and was held prisoner for a dozen years. During this period，he learned the Hun language，and got to know well the geography of their territory. Escaping from the Hun encampment, Zhang Qian made his way back to Chang’an，with only one companion left of the 100 who had set out.

In 119 BC，Emperor Wu sent Zhang Qian on a second diplomatic mission to the Western Re-gions. This time，he had an entourage of 300，with tens of thousands of cattle and sheep anda large amount of gifts.They visited many countries，and these coun-tries sent envoys to return their visit to the Han court.From then on，the Han Dy-nasty had frequent contacts with the countries in the Western Regions，later setting up a Western Regions Frontier Command in today’s Xinjiang Uygur Autonomous Re-gion，which was under the administration of the central government. The Silk Road was another outcome of Zhang Qian’s journeys.

The Silk Road started from Chang’an in the east and stretched westward to reach the eastern shore of the Mediterranean Sea and the Roman Empire. Trade caravans from China carrying large amounts of silk fabrics exchanged merchandise with traders from Persia，India and Greece, and brought home walnuts, grapes and carrots from abroad. In the fol-lowing several centuries，Sino-Western exchanges mainly characterized by the silk trade were mostly carried on through the Silk Road.