The chinese city wall originated in the period of LongShan Culture of the late primitive society. It was a kind of defense work developed from the ditches and gradually became the chief way of city protection instead of the ditches.
After the development If architectural skills in Xia and Shang dynasties, the city walls had been widespreadly built in the prtiod of Western Zhou Dynasty; "the city" and "the empire" had the same meaning at that time, and the building skills also developed to a new level, which was quite similar to that of today.
Although the city and market emerged very early, there were no relations between them at all. It was because there were markets in the city that the earliest chinese cities appeared in the period of Western Zhou Dynasty. The term "city" was primarily used in books in the warring states period. It is said that "A region with markets in it and surrounded by the walls was called A City."