According to archaeological information, the history of the Guangdong people can be dated back to the Maba people, who lived around 100,000 years ago. During the Shang and Western Zhou dynasties (c. 16th century - 771 BC), Guangdong ancestors started trading and cultural exchanges with the Shang and Zhou kingdoms in Central Plains (comprising the middle and lower reach of the Yellow River). In 221 BC, Guangdong underwent an administrative division for the first time. After the establishment of the People's Republic of China, Guangdong made mild administrative adjustment based on historical divisions. In 1988, the province was divided into 18 (later 21) prefecture-level cities and applied a system whereby the prefecture-level cities manage the counties and the towns manage villages. The management system is used to this day.