It was not until the fall of Western Jin during the early 4th century AD that northern Chinese moved to Jiangnan in significant numbers.

The Yellow River valley was becoming barren due to flooding, lack of trees after intensive logging to create farmland and constant warfare during the upheaval of the Five Barbarians.

One notable example of this was when the Song dynasty fell in the north, large numbers of northern refugees flooded into the relocated capital Hangzhou mainly from the areas that are currently under the administration of modern-day Henan Province.

Within just 30 years, contemporary accounts record that these Northern immigrants outnumbered the Wu natives of Hangzhou, altering the city's spoken dialect and culture.

[3] In addition, 5 out of 12 Nobel laureates who are of Chinese descent are Wuyue people, including Tsung Dao Lee, Charles Kao, Steven Chu, Roger Tsien and Youyou Tu.