Friends familiar with the history of the Warring States should know that the founding prince of the State of Wei (the first monarch) was Wei Wenhou Weisi. Interestingly, according to historical records, after Wei Wenhou succeeded to the throne, he was not the monarch of the State of Wei but the ruling Zhengqing of the State of Jin, and even the famous "Li Wu Transformation Law" was also implemented by Wei Wenhou in the name of Zhengqing of the State of Jin. So why was Wei Wenhou able to concurrently serve as the zhengqing of the Jin state?
As we all know, the "Three Branches of Jin" is recognized as the beginning of the Warring States. However, what is less known is that the "three branches of jin" are actually the collective name of many historical events such as the destruction of wisdom by the three families, the three palm jin, the three feudal princes, and the three branches of the jin. It lasted nearly eighty years, from the joint destruction of the Zhi family by Zhao Weihan in the sixteenth year of King Zhending of Zhou (453 BC) to the fall of the Jin state in the twenty-sixth year of King An of Zhou (376 BC).
After Zhao Weihan jointly destroyed the Zhi family, the then Jin monarch Jin Chugong wanted to take advantage of the opportunity to take the Zhi family's territory for himself. However, Zhao Weihan divided up the territory of the Zhi family, and did not even leave a single piece of soil for the Duke of Jin. The enraged Jin Dynasty borrowed troops from Qi and Lu to attack the three families, but was defeated by the three families. The Duke of Jin fled and died in the State of Chu, and the three families established the Duke of Jin as the new Monarch of the State of Jin.
The defeat of the Duke of Jin marked that the three families of Zhao, Wei, and Han had completely taken control of the Jin state, and the Jin monarch had completely become a puppet. By the time Duke You of Jin succeeded to the throne, the son of Duke Ai of Jin, all the territories of the Jin state (except for the two provinces of Qi and Quwo) had been divided among the three families. As the monarch of the state, the Duke of Jin You, instead, had to personally go to see the lords of the Zhao, Wei, and Han families as courtiers, and the Jin state was already effectively destroyed.
However, for various reasons, the three families of Zhao Wei and Han did not become official princely states, and were nominally "Qing Dafu of the Jin State". Because of this, the heads of the three families of Zhao Wei and Han, who had become the actual monarchs, were still taking turns to serve as the zhengqing of the Jin dynasty. In the first year of King Weilie of Zhou (425 BC), Zhao Xiangzi, who was then the Zhengqing of the Jin State, died, and Wei Si, the head of the Wei family, succeeded him as Zhengqing of the Jin State according to the custom.
At this time, Zhengqing of the State of Jin was no longer the ruling master of the State of Jin, but the ally of the three families of Zhao Wei and Han, and Wei Si also used the identity of the Zhengqing of the State of Jin to build a "Three Jin Alliance" that was crucial to the hegemony of the State of Wei. In the twenty-third year of King Weilie of Zhou (403 BC), Zhou Tianzi officially made Zhao, Wei, and Han princes, and Wei Si became the last Zhengqing of the Jin State and the founding prince of the State of Wei, and was the Marquis of Wei.