From "Ba" to "Chongqing", the name of Chongqing has experienced many historical changes. In the Western Zhou Dynasty, it was the capital of Pakistan, a vassal state. In the twenty-sixth year of Qin Shihuang (22 1), the world was divided into thirty-six counties, and Ba County was one of them. Ba County was called Jiangzhou in Han Dynasty. During the Wei, Jin and Southern and Northern Dynasties, it was renamed Jingzhou, Yizhou, Bazhou and Chuzhou. In the first year of Emperor Yangdi Huang Kai (AD 58 1), Liangzhou was changed to Yuzhou (because Jialing River was called Yujiang in ancient times), which was soon abolished by the Tang Dynasty. The first year of Chongning in the Northern Song Dynasty (1 102) was changed to Duke Zhou. Xiaozong ascended the throne in the Southern Song Dynasty and made his third son King Gong. In the sixteenth year of Xichun (1 189), Zhao Dun succeeded to the throne. Half a year later, he was promoted to the secretariat of the Duke of Zhou, boasting "double happiness", so he upgraded the Duke of Zhou to the secretariat of Chongqing. Since then, it has been called "Chongqing". Yuan was Chongqing Road, and it was still Chongqing Prefecture in Ming and Qing Dynasties. Chongqing 1929 was established, and 1997 was promoted to a municipality directly under the central government in March.