Yu Gong
Before the state of Qin unified China in 221 BC, each region had its own unique customs and culture, although all were dominated by an upper class that shared a largely common culture. In the "Yu Gong" (Tribute of Yu), a section of the Book of Documents which was most likely composed in the 4th century BC, the author describes a China that is divided into nine regions, each with its own distinctive culture and products. The core theme of this section is that these nine regions are unified into one state by the travels of the eponymous sage, Yu the Great and by sending each region's unique goods to the capital as tribute. Other texts also discussed these regional variations in culture and physical environments.