Cao Pi said something to the prince before he died, which actually led to Cao Wei being usurped by Sima Yi.

Sima Yi was not prominent in Cao Cao's era, but he truly came to power during Cao Pi's era. Cao Pi has always trusted Sima Yi very much. Before he died, Cao Pi pointed to Sima Yi, Cao Zhen, and Chen Qun and said to Prince Cao: "These three are our loyal ministers in Wei. Don't doubt them!" During his reign, Emperor Wei Ming always kept his father's last words in mind and trusted Sima Yi. Before the death of Emperor Wei Ming, Sima Yi was still appointed as the minister. What Cao Pi said before his death undoubtedly paved the way for Sima Yi to usurp power and Cao Wei's fall.

Cao Cao has always been skeptical of Sima Yi. During Cao Cao's time, Sima Yi was always cautious and thus saved his life. When Cao Cao was in power, Sima Yi's official position was always very low, and the highest one was the crown prince's concubine. Cao Pi trusted Sima Yi very much. When Cao Pi was the crown prince, Sima Yi was his confidant. After Cao Pi succeeded to the throne, Sima Yi's official position rose like a rocket. Within a few years, he served as an official for the ministers, recorded their affairs, took control of the military, and became the de facto prime minister.

When Cao Pi conquered Wu, Sima Yi was appointed to stay behind, asking him to appease the people and be responsible for logistics. Cao Pi also publicly stated that when he was in the east, Sima Yi was in charge of the west; when Sima Yi was in the west, he was in charge of eastern affairs. Cao Pi didn't just talk, he really did it. When Cao Pi was in the capital Luoyang, Sima Yi was ordered to guard Xuchang. Xuchang was the capital of the late Han Dynasty, with a status comparable to Luoyang.

Before his death, Cao Pi appointed Sima Yi, Cao Zhen, Cao Xiu, and Chen Qun as auxiliary ministers. He also told Emperor Wei Ming not to doubt Sima Yi and others. It can be said that Cao Pi regarded Sima Yi as Zhuge Liang of Wei. Emperor Wei Ming himself trusted the young people of his generation, such as Cao Shuang. But because of his father's entrustment, he continued to reuse Sima Yi and others.

Sima Yi was responsible for fighting Zhuge Liang all year round, so he controlled Wei's most elite Guanzhong Corps and cultivated a large number of cronies in the army. Sima Yi also killed the rebel Meng Da and pacified the Liaodong separatist force Gongsun Yuan, thereby gaining a more stable position. During his lifetime, Emperor Wei Ming still regarded Sima Yi as his most trusted veteran minister and appointed him as an auxiliary minister. Unexpectedly, Sima Yi, the most trusted person in the eyes of Cao Pi and Cao Cao, eventually usurped the power of Cao Wei.

Cao Pi bears the greatest responsibility for the rise of Sima Yi's power. Cao Pi had known Sima Yi for many years, but had never doubted him. He regarded Sima Yi as Zhuge Liang, and before his death he told his son not to doubt Sima Yi. This is really a mistake. Liu Bei said that Zhuge Liang was ten times more talented than Cao Pi, and was not really belittling him. Cao Pi's taste in people is really bad. "Historical Collection" is original, and all major platforms have opened up original protection and signed a contract with "Rights Defense Knight". Plagiarism will be investigated!