In ancient China, the marriage system practiced monogamy and polygonal concubinage, although each child was nominally the child of the main wife, but due to the difference in kinship, in order to maintain the order of the family and the continuation of the patriarchal law, the primogeniture inheritance system was adopted.
The eldest son born to the wife has priority in inheritance. This system has been used since the Zhou metric system and has become one of the core systems of China's patriarchal society. Its implementation principle is "to establish a descendant to be long not to be virtuous, and to establish a son to be noble rather than long".
Regardless of age, the son-in-law born to the main wife is the first heir in line to the throne, and only the main wife has no children, and the concubine is eligible to inherit. Even if the other sons in law are not virtuous or intelligent, they have the right to inheritance priority in order of age.
This is the inheritance system of "having a descendant and establishing a long-term heir".
In ancient China, the eldest son of a monarch was usually the crown prince. Although in some cases, the eldest son was able to ascend to the throne, this is quite rare. Usually, there are only three situations in which a concubine can become a prince: first, the concubine is already old, and the queen has not had children (such as Liu Rong, the first prince of Emperor Jing of the Han Dynasty); second, the mother of the concubine first became the empress (such as Emperor Wu of the Han Dynasty); The third is that the concubine was passed to the queen and became the concubine (such as Li Zhong, the first prince of Tang Gaozong).
At the beginning of the establishment of the Ming Dynasty, the primogeniture inheritance system was more strict, because Zhu Yuanzhang, the Taizu of the Ming Dynasty, in order to maintain family harmony, stipulated detailed clan etiquette, division and inheritance issues.
For example, the Emperor's Ancestral Teachings stipulate that the eldest son of the crown prince and the prince will receive a golden book and a golden treasure, and that the eldest son of the prince will become the prince when he reaches the age of ten.
If the concubine usurps the position of the concubine, he will be demoted to a concubine at the least, or exiled to a distant land. If the prince does not have a concubine before the age of fifty, his concubine will be crowned the prince of the county.
If the prince's concubine still does not give birth to a concubine at the age of fifty, then the eldest son will be made the prince's son.
This system designed by Lao Zhu fully guarantees the inheritance right of the eldest son, and the eldest son of the prince will be recognized as the heir to the throne after the age of ten, and the rest of the sons and concubines can only obtain the title of county king.
If the prince does not have a son-in-law, then the eldest son can be promoted from the prince of the county to the prince when the princess reaches the age of fifty and can no longer have a son-in-law. This system was known as the "Waiting for Succession System" and was strictly enforced among the princes of the Ming Dynasty.
For example, Zhu Chengyong, the seventh king of the Qin Domain, was promoted to the rank of vassal king as the eldest son. The family of Zhu Meigui, the king of the Jin Dynasty, is the most typical example of the system of waiting for the heir.
Zhu Meigui is the grandson of King Zhu of Jin Gong and the eldest son of King Zhu Jixi of Jinding. He was made a prince at the age of only 7 in the third year of Yongle (1405). However, since he had no son-in-law, after his death, Zhu Zhongxuan, the eldest son of the concubine, was named King of Jin and called King Jinzhuang.
Compared with Joo Jong-hyun, Joo Mi-gyu's descendants are much luckier. His son Zhu Qiyuan was named the son of the world when he was 10 years old because he was the eldest son. Zhu Qiyuan's eldest son, Zhu Biaorong, was also named a grandson when Zhu Qiyuan was 10 years old.
Although Zhu Biaorong's great-grandson Zhu Zhiyang is also a concubine, Zhu Biaorong died when he was 5 years old, so Zhu Zhiyang naturally does not need to be a grandson, so he was named a great-grandson at the age of 10.
It is worth mentioning that Zhu Zhiyang's title of great-grandson is unique in the Ming Dynasty, and there is no other similar situation. Although the "Emperor Ming Zuxun" does not stipulate the principle of establishing the heir of the Son of Heaven, the royal family, according to the sentence "the eldest son of the crown prince is the emperor's grandson, and the second son and concubine are all crowned county kings at the age of ten", as well as the practice of the patriarchal system, the Ming imperial family should have initially implemented the system of waiting for the heir.
Ming Xuanzong himself was canonized as the emperor's grandson in the ninth year of Yongle (1411), and this system was followed. Other dynasties also implemented the system of waiting for heirs to a greater or lesser extent, but it was not as strict as that of the Ming Dynasty.
Because if the eldest son is appointed as the crown prince early, then the queen will give birth to the eldest son, and the status of the concubine will be inverted, which is not conducive to the stability of the regime.
Ming Xuanzong made up for the consequences of destroying the primogeniture inheritance system because of the policy of abolishing the latter, but this move still made him criticized. The system of "the East Palace does not treat the heirs, and the Yuan sons do not merge with the seals" established by him broke through the boundaries of the heirs, only talking about the eldest and youngest, so that all princes are in an equal position in terms of inheritance.