Li Longji in history: The court turmoil was eliminated in the early stage, and the Tang Dynasty reached a new peak under his administration. However, in the later period, Li Longji began to fall (as would any head of state who had been in power for too long). This is the so-called "Tianzi Dementia", such as Liu Gai, Sun Quan, Xiao Yan, Sui Wendi, Li Hong and so on. ) His appointment of Li Linfu as prime minister should be the beginning of the corruption of the central government in the Tang Dynasty, and then he appointed Yang and favored An Lushan, which made the central government more corrupt. As a result of the Anshi Rebellion, the Tang Dynasty never returned to the golden age, the people were destitute, the territory of China was greatly reduced (smaller than that of the Qin Dynasty), the governors were separated, the central eunuchs played politics, and the people were destitute.
The disaster caused by Li Longji was not basically eliminated in China until the Song Empire and Liao signed the "Separate Yuan Agreement" in A.D. 1004. My evaluation of Li Longji: early wise, late fatuous.
As for Yang Yuhuan, she is just a woman in Li Longji. What influence can she have on history?