禹貢
Pei Xiu's preface describes geographers in the Xia, Shang and Zhou dynasties, although the earliest known geographical work was the "Yu Gong" chapter of the "Shu Ji" or "Book of Documents", compiled in the fifth century BCE during the mid Zhou period. Pei Xiu also referred to Xiao He (died 193), who assembled the maps made during the fall of the Qin dynasty. This was done after the founder of the Han dynasty, Liu Bang (died 195 BC), had sacked the city of Xianyang. Pei Xiu states: