The maritime Silk Road, like its overland counterpart, had its origins during the Han Dynasty (202 BC-AD 220 ). Although vast seas separate the four corners of the Earth, with advances in shipbuilding and navigational technologies, maritime transport came to provide unprecedented access to the most distant destinations.
It is known that the bulk of the raw and processed silk transported along the overland Silk Road during the Han Dynasty was produced primarily along China's southern coast and in the coastal Wu, Wei, Qi, and Lu regions (present-day Shandong Province). Since ancient times, these areas have been thriving centers of shipbuilding as well as silk production. They were thus able to supply both commodities for export and the means to transport them across the sea.
It was this combination that provided the social and material conditions necessary for the development of maritime trade during the Han Dynasty. The maritime routes opened by Emperor Han Wudi (reigned 140-87 BC) provided access to the Roman Empire via India. This enabled China to actively seek out overseas markets and establish foreign trade relations, and laid the foundation for the development of the maritime Silk Road.
(ChinaCulture.org June 17, 2005)