The choice of empress had been an immediate issue after Cao Pi became emperor in 220.

Lady Zhen was his wife, but by this point had long lost favor due to a variety of reasons including the struggle she had with a favorite concubine of Cao's, Guo Nüwang.

Lady Guo used the unlikely possibility that Zhen's son Cao Rui might be biologically Yuan Xi's son to full advantage in creating conflicts between Cao Pi and Lady Zhen.

Cao therefore had refused to summon Lady Zhen to Luoyang after he ascended the throne but instead ordered her to remain at Yecheng, which caused Lady Zhen to be resentful.

When words of her resentment reached Cao, he became angry and forced her to commit suicide.

In 222, Cao had created Consort Guo empress.

Empress Guo, however, is without make issue.

Lady Zhen's son Cao Rui is the oldest of Cao Pi's sons, but because she had been put to death and because of Cao Pi's lingering doubt as to his paternity, has not been created crown prince.

but instead had been made only the Prince of Pingyuan following Cao Pi's ascension.

Cao Pi, however, does not appear to have seriously considered any other son as heir.

(It might have been because the other sons were all significantly younger, although their ages were not recorded in history.)

In the summer of 226, when Cao Pi is seriously ill, he finally creates Prince Rui crown prince.

On his deathbed, he entrusts his successor to the care of Cao Zhen, Chen Qun, and Sima Yi.

Following Cao Pi's death, Prince Rui ascends the throne at the young age of twenty-one.