Cao Cao had seven daughters, in fact, he only married his three daughters to Emperor Xian of Han, not seven daughters, and the reason for this statement is only to exaggerate that he "blackmailed the Son of Heaven to order the princes". What we know is that Cao Cao used the control of Emperor Xian of Han to achieve his goal of unifying the world, although Emperor Xiandi of Han said that although he was the emperor in the mouth of the common people, the power of the state was in the hands of the famous Cao Cao, and Emperor Xian of Han was just a puppet emperor.
Just like a liar, if you tell a lie too much, you have to use other means to round up your last lie, then Cao Cao is such a person. Cao Cao had been relying on the name of the Han Dynasty for so many years to unify the Central Plains and realize his great cause of unification. Emperor Xian of Han also became his deputy, becoming a tool for him to dominate the world, but for such a long time, Cao Cao and Emperor Xian of Han had lived in a relationship of monarch and subject, and if they were to be broken on the surface, it would naturally be detrimental to their dream of unifying the world. Therefore, Cao Cao would use other methods to control Emperor Xian of Han, not only not to shake the position of Emperor Xian of Han, but also to continue to realize the plan.
Since ancient times, there have been many monarchy states that have married their sons and daughters to handle relations, so Cao Cao also wanted to marry his three daughters to Emperor Xian of Han. Therefore, in the eighteenth year of Jian'an in the Han Dynasty, Cao Jie, Cao Xian, and Cao Hua married Emperor Xian of Han and became his concubines, and in the second year, they were promoted to nobles. In doing so, he had the opportunity to further control the Han Dynasty. However, at that time, Emperor Xiandi of Han and his own Empress Fu had a good relationship, and the second rebellion plotted by Emperor Xiandi of Han at that time was planned by Empress Fu.
In the nineteenth year of Jian'an, the second rebellion of Emperor Xian of Han was revealed, and Cao Cao knew about it, so he killed the sons of Fu Quan (that is, Empress Fu's father) and all the old and young people in the Fu family, and also exiled the two children of Emperor Xian of Han and Empress Fu, and finally Empress Fu did not survive and was killed by Cao Cao. So in the same year that Empress Fu was killed, Cao Cao's three daughters were made nobles, and the second daughter Cao Jie was made the new empress.
In fact, at that time, Empress Fu and Emperor Xiandi of Han conspired to eliminate Cao Cao, we can analyze it, when Cao Cao suddenly married his three daughters to Emperor Xiandi of Han, as the main palace, the natural pressure was great, and she herself knew that this actually strengthened cao Cao's control of the power, like sitting on a needle felt. At that time, Cao Cao also asked Emperor Xian of Han to break through the bottom line and make him the Duke of Wei, as well as land, to establish the Zongmiao Sheji, so that Emperor Xian of Han was also very big, so the couple carried out a plan to eradicate Cao Cao under such great pressure, and did not want to fail.
Empress Fu was dead, plus Cao Cao had killed a pregnant wife of Emperor Xian of Han before, and Cao Cao had married three daughters to Emperor Xian of Han, which seemed interesting and generous to Cao Cao on the surface. In fact, it can not only appease Emperor Han Xian, but also have three eyeliners, so that even if Emperor Han Xiandi has the slightest plan, then Cao Cao will definitely know it well.
In this way, cao Cao's safety was fully grasped with the help of his three daughters, and the original relationship between the monarch and the subject was further advanced, and now it is the relationship between father-in-law and son-in-law. Cao Cao could also more legitimately control Emperor Xian of Han and implement his series of plans to unify the world and "blackmail the Son of Heaven to order the princes".
In fact, Cao Cao's doing so was also a good thing for Emperor Xiandi of Han, at least his later life was safe. Although Emperor Xian of Han did not realize the revival of the Eastern Han Dynasty and could only play a puppet role, when he abdicated, Cao Cao's second daughter Empress Cao Jie and Emperor Xian of Han had a very good relationship with each other, and she was also loyal to the Han Dynasty.
After the abdication of Emperor Xian of Han, he was named the "Duke of Shanyang" in his fiefdom and enjoyed extremely high treatment, in fact, he exchanged a han dynasty that was doomed to lose in exchange for a happy life in his later years, which was also very drawn, and there were not many emperors like him who lived in his old age, which was also a kind of fate of his own.