What do the four famous saints in the history of calligraphy refer to?

The "four sages of calligraphers" refer to Zhang Zhi, Zhong You, Wang Xizhi and Zhang Zhi, the "sage of grass" in the last years of the Eastern Han Dynasty, Zhong You, a scribe and regular calligrapher in the Cao and Wei Dynasties, and the ink of Wang and his son in the last years of the Eastern Jin Dynasty, which can be called "unique in ancient times". In order to prove the objectivity of his unique point of view, the author quoted a sentence from Wang Xizhi, a calligrapher with a high position and a clear pronunciation: "Looking at all the books, Zhong and Zhang Xin are second to none, and the rest are insufficient." On the other hand, Wang Xizhi absorbed the essence of Zhong and Zhang and pushed the art of calligraphy to a new height. Therefore, Yue Ji always says: "There was a bell in the Han and Wei Dynasties, and Zhang Jue, and there were two kings at the end of Jin Dynasty." These four are called the "four saints" of ancient calligraphers. Zhang Zhi, whose name is Boying, is from Dunhuang. The date of birth is unknown, and he died in the third year of Chu Ping of Emperor Xian of Han Dynasty (about AD 192). He was born in Jiuquan, Dunhuang (now Gansu), and his father Huan was Tai Changqing, who moved to Huayin, Hongnong. The son of the famous minister Boying is young and energetic. He is diligent in learning from the ancient times, walking in the Ming Dynasty, and prostrating himself to the court. Therefore, he is called Zhang Youdao, and he is a white man who avoids the world. If you are good at zhangcao, you will get rid of old habits, save zhangcao and point out pictures, and become a "modern grass." "Shu Duan" said that he "learned the method of Cui (Yuan) and Du (Cao), so he changed it to this grass. The font is made in one stroke, occasionally interrupted, with continuous blood and even staggered veins. " Zhong You (15 1-230) was a calligrapher and minister of Wei during the Three Kingdoms period. Yingchuan Changshe (now Changge, Henan) was born. At the end of the Eastern Han Dynasty, he named Lian Xiao Tingwei and assistant minister of Huangmen. Cao Cao was in power and served as a deputy commander in the central and ministerial departments. Cao Pi replaced Han and Ren Tingwei, and sealed the noble township. Ming Di acceded to the throne and moved to be a teacher, known as "Zhong Taifu". Gong's calligraphy is unique, especially represented by Li and Kai. If books fly in the sea, cranes jump in the sky. Later generations commented that he was fascinated by his official career, which was very exciting. He and the great calligrapher Zhao Hu called him "Hu Fei Zhongshou". Also known as "Zhong Wang" with the King of Jinxi. On my deathbed, the teacher will say, "I think hard and learn to use a pen." Every time I see 10 thousand kinds, I paint, and I paint so intently. " Wang Xizhi (32 1-379, or 303-36 1), whose real name was Shao Yi, was born in Linyi (present-day Shandong), and later moved to Yin Shan (present-day Shaoxing, Zhejiang) as the general of the right army. He was a great man in the Eastern Jin Dynasty. His son Wang Xianzhi's handwriting is also very good. People call them "Two Kings", and another son, Wang Ningzhi, is a general of the right army, and is called "Wang Youjun" and "Wang Huiji". Representative works include: Le Yi Lun in regular script, Huang Ting Jing, Seventeen Guas in cursive script, Gua for Aunt in Running Script, Gua for Quick Snow Clear, Gua for Mourning, Preface to Lanting in Running Script, etc. Wang Xianzhi (344 -386), a calligrapher and poet in the Eastern Jin Dynasty, was born in Huiji (now Shaoxing, Zhejiang) and the seventh son of Wang Xizhi. In order to distinguish it from later calligrapher Wang Min, people called it Wang Daling. He and his father are also called "two kings". Wang Xianzhi practiced calligraphy with his father since childhood, and he was very ambitious. Later, he regarded Zhang Zhi as a whole. He is famous for his running script and cursive script, but he also has a deep foundation in regular script and official script, because Tang Taizong didn't appreciate his works very much, and his works were not as many as his father's. The masterpiece "Thirteen Lines of Luo Shen Fu" handed down from ancient times is also called "Thirteen Lines of Jade Edition".