Wang Xizhi in the Jin Dynasty was rich in calligraphy theory, and also formed a new running script and patriarchal clan system.
Mature regular script ou, Yan, Liu and Zhao.
In the Tang Dynasty, Sun made a cursive classic "Book Score" with his wonderful cursive script, which left an extremely valuable wealth for future generations. "Naughty in ancient times, different disadvantages in today" laid the foundation of calligraphy aesthetic theory.
Shu Tong, a great master.