Because Wu Zetian is the daughter-in-law of the Li family after all, and her sons are all surnamed Li, even if she changes her title to Zhou, it will eventually be passed on to her children, who are also the children of the Li family. The surname Li came to inherit the throne, and her Jiang returned to the hands of the Li family through non-war means.

After Wu Zetian proclaimed himself emperor, she changed her country name to Zhou, because Wu's ancestor was that Wu Zetian hoped that the Wu Zhou Dynasty with her resume would be prosperous. In fact, Wu Zetian wanted Wu Shi's people to inherit the throne. Later, Wu Zetian appointed Li Dan as the heir, which means to tell everyone that Li Dan is only my son, not a prince, and indirectly told the descendants of Wu that you still have a chance to compete for the throne.

On the other hand, Wu Zetian thought about the blood relationship. If it is passed on to her nephew, then as an aunt, she must have nothing to do with her parents, and she has a son. So where to buy a son? Maybe after weighing the pros and cons, she is determined to return the country to the Li family.

But later, Wu Zetian also suppressed Li Dan in the dark. Li Dan's two favorite princesses disappeared in Wu Zetian's palace. Li Dan knew this and that his mother wanted to suppress him, but she still defended Li Dan. Her nephew falsely accused Li Dan of rebellion, took Li Dan away, tortured her, and tried to extract a confession. After Wu Zetian learned about this, she tried her best to defend Li Dan, which saved him.

Wu Zetian also knows that Wu's children have no talent for governing the country. They only know that flattery is difficult to achieve great things and their conduct is arrogant. They have offended many people and are not suitable candidates, so they are more determined to pass on the throne to their sons. Finally, he made his son Li Xian a prince.