Ningbo was one of China's oldest cities with a history dating back to 4800 B.C. the Hemudu culture. Ningbo was known as a major trading port along with Yangzhou and Guangzhou in the Tang dynasty; thereafter, the major ports for foreign trade in the Song dynasty. Ningbo was one of the five Chinese treaty ports opened by the Treaty of Nanjing (signed in 1842) at the end of the First Opium War between Britain and China. Ningbo was once famed for traditional Chinese furniture production.