While Ban Chao was occupied with pacifying the Western Regions and maintaining the safety of the Silk Road, he dispatched his Subaltern, Gan Ying, on several missions to establish contact with the Roman Empire.

One of these expeditions took place in the ninth year of the Yongyuan reign period (AD 97 ). Gan Ying and his entourage departed from the kingdom of Qiuci (present-day Kuche, Xinjiang), passing through Tiaozhi (Characene and Susiana, present-day Iraq) and crossing Anxi (Parthia, present-day Iran) to its western border, the shores of the Persian Gulf. This was the farthest west that any Chinese emissary had yet penetrated.

However, Anxi (Parthia), was not willing to allow the Han Dynasty (202 BC - AD 220) direct access to the Roman Empire, because this would threaten their control of the trade in Chinese silk with the West. They therefore greatly exaggerated the difficulty of crossing the sea, inducing Gan Ying to halt his expedition and return to China. Although this expedition did not reach the Roman Empire, it greatly enriched Chinese knowledge of the countries of Central Asia.

(ChinaCulture.org June 23, 2005)