Great Wall of China The Great Wall (長城) originated during the Warring States Period, when the states of Qin, Wei, Zhao, Qi, Yan, and Zhongshan built extensive fortifications to defend their borders. Qin Shi Huang prevailed over all rival states and unified China in 221 BC, establishing the Qin dynasty; with the intention of imposing centralized rule and preventing the reemergence of feudal lords, he ordered the destruction of the wall sections that divided his empire along the previous state borders. To define and defend the empire's territory against the Xiongnu people from the north, he ordered the construction of new walls to connect the remaining fortifications along the empire's northern frontier.