Liu Bang established the powerful Han Dynasty in 206 BC. During
the Han Dynasty, agriculture, handicrafts and commerce flourished,
and the population reached 50 million. During his reign (140-87
BC), the most prosperous period of the Han Dynasty, Liu Che,
Emperor Wudi, expanded the territory of the empire from the Central
Plains to the Western Regions (present-day Xinjiang and Central
Asia). He twice dispatched Zhang Qian as his envoy to the Western
Regions, and in the process pioneered the route known as the "Silk
Road" from Chang'an (today's Xi'an, Shaanxi Province), through
Xinjiang and Central Asia, and on to the eastern shores of the
Mediterranean. China's gorgeous silk goods were traded to the West
along the Silk Road. As contacts between East and West increased,
Buddhism spread to China in the first century AD. In 105, an
official named Cai Lun, synthesizing the experience of those before
him, discovered a technique for making fine paper, an invention
that led to a revolution in communications and learning.?