Li Yuan was the emperor and had boundless power. Li Shimin was just a prince. Even if he launched the Xuanwumen coup and killed Li Jiancheng and Li Yuanji, it is reasonable to say that Li Yuan is the emperor after all, and it will be easy for him to oppose Li Shimin. However, Li Yuan always admitted that he surrendered his military and political power to Li Shimin at that time. Then, three days later, he made Li Shimin crown prince. Two months later, Li Shimin was put on the throne. How could Li Yuan behave like this? On this issue, we should go back to the scene at that time and analyze it in detail.
Xuanwumen intercepted and killed Li Jiancheng and Li Yuanji, Li Shimin bribed in advance, and Zhonglang, who was on duty at Xuanwumen that day, would be Chang He. Unbeknownst to them, Li Jiancheng and Li Yuanji found that they had been deceived after entering the trap, and it was too late to escape, and as a result, both of them were killed. Although more than 2,000 soldiers from the Prince's Mansion and the Qi Dynasty came to the rescue, it was too late, and the heads of Li Jiancheng and Li Yuanji instantly disintegrated. This story is recorded in the history books, and although the details are "beautified" with tendencies, the original appearance is not difficult to restore. However, after solving Li Jiancheng and Li Yuanji, only a small part of the coup was completed, and if Li Yuan intervened, Li Shimin would have to tie his hands and capture it, and the result would be nothing more than a lose-lose situation, which is obviously not what Li Shimin wants to see, so holding Li Yuan hostage is a crucial step!
For Li Shimin's sharp edge, Li Yuan is also aware of it, but the benevolent Li Yuan is painfully hesitant in the face of the situation of several sons becoming water and fire, and does not know how to be good, for him, Li Jiancheng is the eldest son of the concubine, and has also made a lot of merit, so he did not think of changing the crown prince, and Li Shimin wanted to seize the throne, only through the coup d'état, Li Yuan was also aware of Li Shimin's ambitions, but he and Li Jiancheng still proceeded from the perspective of family affection, and did not expect that things would eventually develop into serious consequences. Therefore, when Li Shimin framed Li Jiancheng and Li Yuanji for defiling the harem, Li Yuan did not expect that Li Shimin was going to launch a coup d'état, and the "stunned" Li Yuan returned from the shock and let their three brothers face to face in the palace tomorrow morning.
After Li Yuan ascended the throne, he knew that his power was falling by, and he was disheartened, so he did not interfere in political affairs at all, and Li Shimin was also very respectful to his father on the surface, and he built the Daming Palace in a big way to make his father's pension and pleasure place. Li Yuan understood his meaning well, and he became the Emperor Taishang. Although Li Yuan's practice was self-preservation, it was also conducive to reducing court contradictions and creating a good environment for Li Shimin to display his great talents without distraction. In May of the ninth year of Zhenguan (635 AD), Li Yuan fell ill and died at the age of 71. The courtesy name is "Emperor Shenyao Dasheng Daguangxiao", and the temple name is "Gaozu".