The crux of the matter is that the criterion for judging prime ministers in Tang Dynasty is not official rank, but closely related to the administrative system and the rise and fall of imperial power/relative power in different periods. Throughout the Tang Dynasty, the evolution of prime ministers can be divided into three stages:
1. The governors of the three provinces are all prime ministers.
From the first year of Wude (6 18) to the sixth year of Wude (623), with the length of three provinces, Shangshuling, Zhongshuling (2 people) and Shizhong (2 people) were all prime ministers.
2. Only the prime minister is the person who is in charge of the Chinese book, serves the Chinese book, works with the same company, and works with the same company.
The time limit is from the 23rd year of Zhenguan to the first year of Suzong Gan Yuan (758).
3. Since Su Zonggan Yuan, anyone who is not a minister of Chinese literature or works in Chinese literature has been appointed as prime minister in the name of "Zhang Shi of Tongping".
In addition, after the middle Tang dynasty, the above prime ministers were called "positive phase"; In addition to the "positive phase", the prime minister also has two forms: "making the phase" and "inner phase" (some Hanlin bachelors).
★★★★ Prime Minister rank: The first-class officials in the Tang Dynasty were "three public offices and three divisions" and had no real power; Being a second-class official is the order of the minister, and no one dares to do it, because Li Shimin did it. Therefore, the prime ministers before the mid-Tang Dynasty may be: ministers subordinate to the second class (the actual chief executive of Shangshu Province), ministers subordinate to the third class (the chief executive of Zhongshu Province, renamed as "the order of internal history") and ministers subordinate to the second class (the chief executive of Xiamen Province, renamed as "Yan Na"), or prime ministers of lower rank, but named as "the same chapter".
★★★ So, whether in the period of adding "Pingzhang Affairs and Fengge Luantai" (Pingzhang Affairs and Zhongshumen) or in the period of making literature and history orders (Zhongshumen Governor), Di was one of the prime ministers!