What fonts were popular in calligraphy during the Southern and Northern Dynasties?

Book is the most popular style in China feudal society from the Southern and Northern Dynasties to the Jin and Tang Dynasties. Before the appearance of regular script, China calligraphy had produced three styles: Da Zhuan, Xiao Zhuan and Li Shu. Generally speaking, the ancient characters before Xiao Zhuan are collectively referred to as Da Zhuan, including Oracle Bone Inscriptions, bronze inscriptions and six languages except Qin in the Warring States Period. Xiao Zhuan is a popular script after Qin unified China. On the basis of Qin script, refer to other vassal scripts. In order to facilitate writing, it is standardized and unified. This is the first standardized regular script in the history of calligraphy in China. Official script is another representative character after Xiao seal, which is based on Xiao seal. The appearance of official script is a great revolution of Chinese characters. Its significance lies not only in the symbolization of Chinese characters, but more importantly, it has changed the writing style and aesthetic trend of Chinese characters, thus laying a foundation for the emergence of regular script calligraphy art and further opening up a broad world for the development and prosperity of China calligraphy art.