Fang is not only a famous politician, but also a historian. In the early years of Emperor Taizong, in order to improve politics, achieve great harmony in the world and attach importance to historical experience, there was a famous saying: "Take history as a mirror and you can know the rise and fall." On the premise of summing up historical experience, Emperor Taizong appointed Fang as the editor-in-chief of history books, which initiated the formal revision of history books and set up a history museum for this purpose. Under Fang's organization and leadership, the formal revision of history books is unprecedented. During the Zhenguan period, Yi * * * compiled eight kinds of history books, namely "Zhou Shu" co-edited by Gu and Cen Wenben; The Book of Northern Qi compiled by Li Bai; Yao Silian's Liang Shu and Chen Shu; And Sui Shu edited by Wei Zhi. Among China's 24 official histories, it accounts for one third, making a remarkable contribution. According to the suggestion of Emperor Taizong, Fang also initiated a new system of revising history. The Tang Dynasty was the first dynasty to compile a record of its emperors.