Vietnam, Guangdong, and Yunnan all experienced a major surge in Han Chinese migrants during Wang Mang's reign. Hangzhou's coastal regions and the Yangtze valley were settled in the 4th century by Northern Chinese families from the nobility. Special "commanderies of immigrants" and "white registers" were created for the massive number of Han Chinese of northern origin who moved south during the Eastern Jin dynasty. The southern Chinese aristocracy was formed from the offspring of these migrants; Celestial Masters and the nobility of northern China subdued the aristocracy of southern China during the Eastern Jin and Western Jin, particularly in Jiangnan. With the depopulation of the north, due to this migration of northern Chinese, the south became the most populous region of China.