We all know that Tang Taizong's Xuanwumen changed, killed his brother and brother, successfully ascended the throne, and welcomed his father as Emperor Taishang. Subsequently, he worked hard to create the rule of Zhenguan, which was enjoyed by posterity.
However, Li Shimin made an incomparably bad start, and the impact of this matter can be said to exceed that of the Tang Dynasty generation. The wolf side of the Tang Dynasty royal family also began, and it has been circulating repeatedly.
First of all, we have to start with Li Jiancheng.
As the heir, Li Jiancheng, who conforms to the legal system of the primogeniture inheritance system, is the natural first heir. Why do we always advocate the primogeniture system? This is because as long as the primogeniture system is followed, unless there are major changes (death of the eldest son, the death of the emperor, etc.), there is a high probability that the throne will be passed on smoothly. Moreover, the ministers can also directly take sides with the prince and strengthen the power of the prince, so that they can effectively avoid problems such as infighting in the royal family and usurpation of the throne by the prince. Although Li Jiancheng was generally qualified as a prince, and did not do a bad job. But the problem is that Li Shimin is too good, his merits are almost completely equivalent to fighting the world, and Li Shimin also has his own staff and forces, Li Shimin will inevitably be a little unwilling, in exchange for anyone has a little careful thinking, after all, the temptation of the throne is too great. This also increased the suspicion between the prince and Li Shimin. Therefore, due to various reasons, Li Shimin launched the Xuanwumen Revolution.
Why does Li Shimin have opened an incomparably bad head? Because he used his own body to tell others, Datang does not have the primogeniture inheritance system, as long as you are strong and have a big fist. You can be the emperor, and the old father can be welcomed by you to become the emperor. The consequences of breaking the rules are very serious, which is why our ancestors attached importance to ethics and the system of primogeniture, because if the etiquette and ethics are broken, it will cause terrible consequences. We can't point out any inevitable connection between the Xuanwumen revolution and the internal strife of the Tang dynasty royal family later, but at least, it has opened an incomparably bad head and broken the rules.
First of all, from the perspective of Emperor Taizong's own dynasty, although Li Chengqian was the crown prince, Li Tai and Li Ke's power was also very large, and even seeing that Li Tai was equally favored and thought that he had the idea of taking a wife, Li Chengqian felt threatened. So Li Chengqian tried to assassinate Li Tai, but failed. Therefore, he colluded with Li Yuanchang, the King of Han, Du He, Hou Junji, and others, the princess of Chengyang, and planned to force the palace to force the army first, and also to carry out a "change in Xuanwumen" and the matter was revealed. Li Shimin had no choice but to depose the crown prince as a commoner.
A series of events followed. Although Li Zhi ascended to the throne in the name of the crown prince, after Li Zhi's death, Wu Zetian even deposed his own son and usurped Tang Jianzhou, because of her strong strength, she did not pay attention to the rules. It also created the only female emperor in Chinese history. Li Xian later launched the "Shenlong Coup" and successfully ascended to the throne, overthrowing his mother's rule. However, Li Xian's son Li Chongjun joined forces with the Yulin army generals Li Duozuo, Li Sichong, and Li Qianli the Prince of Cheng to launch a military coup d'état and kill Wu Sansi and his henchmen. However, the coup failed, and Emperor Zhongzong killed Crown Prince Shigetoshi. History calls it the "Jinglong Coup". However, Li Xian's sister Princess Taiping and his wife Wei Hou interfered in politics, wanted to look up to their own example Wu Zetian, and poisoned Li Xian, which is outrageous enough, right? It's not over yet! Li Dan's son Li Longji joined forces with his aunt Princess Taiping to launch a Coup d'état in Tang Long and killed Wei Hou. However, after the two people had a conflict and competed for power, Li Dan had to avoid the struggle to give way to his son Li Longji, who destroyed his aunt after taking the throne, and finally ended this outrageous power struggle.
However, then Li Longji "killed three sons in one day", and the Anshi Rebellion broke out, and Li Longji was welcomed by his own son as Emperor Taishang. Then the political situation of the Tang Dynasty continued to fall into infighting among the members of the royal family, and various forces appeared. Parties, eunuchs, feudal towns and other forces took turns to appear, and the political situation of the Tang Dynasty deteriorated day by day. A good Tang Dynasty thus died alive in the midst of infighting.
This kind of son creates the father's rebellion, the son creates the aunt's rebellion, the family members do not trust each other, the brothers kill the brothers, and even the father kills the son, and the royal family of the Tang Dynasty inevitably falls into internal strife, there is no trust to speak of, mutual suspicion, the ministers take sides with each other, and the parties are numerous. It indirectly led to the corrupt situation of the Tang Dynasty. And this, it has to be said, is inextricably linked to the destruction of rules and vicious struggles.