There was no unified title for the son-in-law of the earliest emperor. According to textual research, Minister Cao Wei was named Xu in the Three Kingdoms. He was also the first son-in-law of the emperor known as a captain Xu in history. However, the son-in-law of the emperor at that time had not been renamed Xu, a captain. Later, Du Yu, the minister of the Jin Dynasty, married Princess Anlu, the daughter of Sima Yi, the emperor of the Jin Dynasty, and was awarded the post of captain Xu. Wang Ji, a general of the Jin Dynasty, was also made a captain after marrying Princess Changshan, the daughter of the Jin Emperor. So then an agreement was formed. The emperor's son-in-law was all named Xu a captain, or Xu for short. But at this time, a surname Xu is no longer an official position. And became the name of the emperor's son-in-law
At first, the emperor didn't pay much attention to choosing a son-in-law or marrying a daughter. But then more and more attention was paid to it. First of all, from the appellation, the princess is not called marriage, but Shang. A man who marries a princess is not called a wife. But married an ancestor. First of all, when a princess gets married, she will build her own princess mansion and live alone. I don't live with Xu. If Xu wants to have sex or meet the princess, he still needs to report in advance. If the princess doesn't agree or the servants in the princess's family don't inform Xu, Xu won't see the princess.
During the Tang Dynasty, whether the emperor married his daughter or promised to marry a princess, there were political purposes. Moreover, Xu Ma in the Tang Dynasty was almost always green. Few people are not cuckolded. This is why there is such a saying as "Tang Gui". In the Tang dynasty, the emperor married the princess in order to win over the ministers and show his closeness to them. The courtiers are willing to marry the princess, on the one hand, because the imperial life is inviolable. On the other hand, it is to improve the hierarchical status of one's family. During the Tang Dynasty, the hierarchy was very obvious. If ordinary ministers or ordinary families want to improve their family status, they must marry the daughters of higher families to improve their family status. For example, Cui Shi, Lushi, Li and Zheng in Tang Dynasty were also related to Longli and Li. These are the most famous families. So many ministers don't care how immoral the princess is in order to raise the family status.
However, the princesses in the Tang Dynasty were the most unruly and despised group in history. According to historical records, princesses in the Tang Dynasty generally hoarded Toy Boy. For example, Princess Gaoyang, the daughter of Emperor Taizong of Tang Dynasty, openly contacted many monks and Taoists. Tang Gaozu's daughter is Li Shimin's sister, so life is even more decadent. Basically, there are countless Toy Boy. Even they will exchange Toy Boy and even introduce them to their niece, Li Shimin's daughter. For example, Princess Gaoyang mentioned above is the most typical example. Even the first female emperor Wu Zetian is countless. This shows how deeply the private life of the princess in the Tang Dynasty was eroded.
And in the ancient patriarchal society, men could have three wives and four concubines. But if you marry a princess, you can't marry a concubine. And I have no right to divorce my wife. But the princess can divorce Xu. The princess is unique to Xu. To put it simply, it is not so much that Xu married the princess. It is better to say that the princess married Xu. In history, some Xu was an "invisible bachelor" all his life. There is a princess's wife, but I can't see her. And you can't divorce the princess or marry a concubine. In this way, I have been playing "invisible bachelor" all my life. And there is a fixed princess who can remarry after Xu's death. When the princess dies, Xu will be widowed. From this, we can see the status of the princess and Xu. But Xu is not without benefits. Since the Song Dynasty, anyone who marries a princess and becomes a husband will be awarded five official positions. Compared with most people, Xu is still a glamorous career. Although there is pain behind. But at least the face doesn't look so miserable!