Pingyao Ancient City was built during the Zhou Xuanwang period from 827 BC to 782 BC, and was the residence of Yin Jifu, the general of the Western Zhou Dynasty. Pingyao City has been the seat of county administration since the Qin government implemented the "county system" in 22 1 BC and continues to this day. Pingyao ancient city experienced vicissitudes and became the most complete prototype of ancient county town in China in Ming and Qing Dynasties. The ancient city we are seeing now is what it looked like after the expansion in the third year of Ming Hongwu (1370). Pingyao city after the expansion is magnificent, with a circumference of 6.4 kilometers. It is the oldest and largest county wall in Shanxi and China.