During the Western and Eastern Han dynasties, Chengdu was the capital of Shu Prefecture, which was the center of politics, economy and culture in the southwest region. Chengdu was prosperous and abundant in products, ranking among “five most important commercial and industrial metropolises” in ancient China, which won it the fame of land of abundance. In 221 AD, Liu Bei proclaimed himself emperor in Chengdu. Since then, the political structure of “three kingdoms” formed. During the Eastern and Western Jin dynasties and the Southern and Northern dynasties, Chengdu was the starting point of the southern Silk Road and played a significant role in the Eurasian economic and cultural exchanges.