There was a very cruel royal rule in history, that is, to "kill mothers and children" that made those harem beauties look different. To put it simply, if your son is made crown prince, then you must die. This impersonal system has only appeared twice in the history of our countryOne was in the later years of Emperor Wu of the Han Dynasty, and the other was at the beginning of the founding of the Northern Wei Dynasty
Emperor Wu of the Han Dynasty Liu Che.
Why did such an impersonal system arise, and what purpose did the rulers have?First of all, Liu Che, the outbreak of the Witch Rebellion made the majestic emperor more and more suspicious, he listened to the words of the traitor Jiang Chong and mistakenly thought that the crown prince Liu Ju was going to rebel, so he sent troops to suppress it, and finally forced the empress Wei Zifu and the crown prince Liu Ju to death.
It stands to reason that there is no owner in the East Palace, and the emperor can choose a new son to be the crown prince. But Liu Che regretted that he had forced Liu Ju to death and had never made a prince. In 94 BC, Mrs. Gou Yi gave birth to the prince Liu Fuling for Emperor Wu of the Han Dynasty. It is said that Liu Fuling was pregnant for fourteen months before she was born, just like the ancient Xianjun Yao.
At the same time, the young Liu Fuling had good health, high IQ, and the style of a father (meaning very similar to Emperor Wu of the Han Dynasty), so he was deeply loved by Emperor Wu of the Han Dynasty. In 87 BC, Emperor Wu of the Han Dynasty appointed Liu Fuling as the crown prince when he was dying, and at the same time ordered the killing of Mrs. Gou Yi
Emperor Wu of the Han Dynasty's purpose in killing Mrs. Gouyi was very clearThat's itIn order to prevent the emperor from being young, the empress dowager interfered in politics. Emperor Wu of the Han Dynasty had long had the intention to appoint Liu Fuling as the crown prince, but he was worried that the lord and young ministers would be weak, and the harem would interfere in politics, so that the Han Dynasty would produce another "Lu Pheasant". Because of the lessons of the Zhulu Rebellion, the impact on the early Han Dynasty was very hugeSo Emperor Wu of the Han Dynasty was worried that history would play out again.
The most decisive way to prevent the harem and relatives from interfering in the government is to give the mother of the new emperor to death, so during the period of Emperor Wu of the Han Dynasty, there was a "killing mother and establishing a son". Later, because Emperor Zhao of the Han Dynasty Liu Fuling had no heirs, the mother of the Yuan Emperor of the Han Dynasty, Liu Zheng, died before his father, Emperor Xuan of the Han Dynasty, gradually the rule of "killing mothers and children" did not exist in the Han Dynasty
Northern Wei territory. 
Emperor Daowu of the Northern Wei Dynasty.
Since the Northern Wei Dynasty, the Northern Wei Dynasty began to implement the rule of "killing the mother and establishing the child".The aim was still to prevent foreign relatives from interfering in politics and consolidating imperial power. We all know that the Northern Wei Dynasty was a regime established by the Xianbei people, and unlike the Han people, the Xianbei at that time more or less had the characteristics of a matrilineal clan, that is, "valuing the mother over the father".
Even Emperor Daowu himself sat on the throne through the power of his relatives, and at the same time, as the emperor, he also knew what the consequences would be if his relatives interfered in politics. Therefore, in order to combat the power of his relatives, Emperor Daowu simply learned from Emperor Wu of the Han Dynasty.
It was not until the period of Emperor Xuanwu that the Northern Wei Dynasty abolished the rule of "killing mothers and children".The reason for the abolition is:Emperor Xuanwu favored Empress Hu and did not want her to die because her son was made the crown prince. There is also a saying that Emperor Xuanwu believed in Buddhism and believed that "killing mothers and children".It is very immoral.
But what Emperor Xuanwu didn't expect was that after Empress Hu's son Yuan Yi succeeded to the throne, the Hu family came to the dynasty as the queen mother, and openly managed the government on behalf of the emperor, not only thatThe Hu family also formed a party for personal gain, and fornicated with Emperor Xuanwu's younger brother King Qinghe and others in the harem, and finally poisoned her and Emperor Xuanwu's son Yuan Yi with her lover
The Northern Wei Dynasty's practice of "killing mothers and children" was for fear that the imperial power would decline, the queen mother or relatives would interfere in the government, and the government and the opposition would be in turmoil and even the world would change hands. After Emperor Xuanwu abolished this practice, it turned out that his Empress Hu really did not want to see the scene of the Northern Wei royal family.
The last thing I have to say is,"Killing mothers and children" was almost used on CixiIn his later years, Emperor Xianfeng was afraid that Cixi would interfere with Emperor Tongzhi's governance of the country with the respect of the Empress Dowager, so he left Ci'an a secret decree to kill Cixi. As a result, after the death of Emperor Xianfeng,Cixi won Ci'an's trust with clever words, and Ci'an burned the secret decree in public, and everyone knew what happened next