Because Cao Mao's phrase "Si Mazhao's heart is well known to all" shows this family's inflated ambition incisively and vividly. In unofficial history, Cao Cao had a strange dream that three horses were grazing in the stable, so it was called "Sanma Valley". In the dream, Sanma is Sima Yi's father and son. If this is true, I am afraid that "Sima's replacement of Cao Wei" is really a fantasy.
It can be seen from the history books left by the Three Kingdoms that Sima Yi made many contributions to the Cao Wei regime. In 2 19 AD, Guan Yu surrounded Fancheng. After the Seventh Army was flooded, Cao Cao tried to move the capital several times to avoid losing his advantage. Fortunately, Sima Yi proposed to unite with Wu Dong and attack Guan Yu at this time, which enabled the Cao Wei regime to survive. After Cao Cao's death, Sima Yi destroyed Liaodong, which solved the worries for the later demise of Shu.
If Sima Yi dies at this time, he will be the absolute minister of Wei Zhongxing, even before Guo Jia. But this man lived too long, and all three Cao Wei emperors were exhausted. At the same time, compared with Sima Yi, Cao Zhen and Cao Xiu, his contemporaries, are a little less talented.
What is even more frightening is that Sima Yi's two sons, Sima Shi and Si Mazhao, are more ambitious than anyone else. After the change of Gaoping Mausoleum, the Sima family controlled the state affairs of Wei. Two years later, Sima Yi died and Sima Shi became the heir. After Wu's offensive was quelled, Sima Shi died unfortunately, and Si Mazhao took over in a hurry. After ensuring the transfer of power, Si Mazhao launched a war to destroy Shu and achieved success. Because of this contribution, Si Mazhao was successfully named King of Jin. After Cao Pi tried to resist being killed, the whole world knew that Cao Wei's luck had run out. In fact, Si Mazhao is only one step away from the throne.
After the establishment of the rulers and the collapse of the world, it was natural. However, it was Si Mazhao's son Sima Yan who finally ascended the throne. Si Mazhao died a few months before this moment (AD 265). It stands to reason that the Sima family, after three generations, followed the hegemony established by Cao Cao, Liu Bei and Sun Quan and unified the whole country. It should carry forward the past and forge ahead. However, no one thought that Sima Yan passed the throne to Sima Zhong. According to historical records, "the prince has always been known for his cowardice." To put it bluntly, Sima Zhong's IQ is a little low.
More unfortunately, since Sima Shi, the hidden dangers of nomadic people in the north have not been solved. At the same time, Sima Yan sealed the prince of the same clan before his death, which turned back the clock. The princes were so confused about the emperor that they had the idea of replacing him, and the "Eight Kings Rebellion" broke out. After this ordeal, the family wealth laid down in Sima Yi's era almost disappeared. In addition, Xiongnu, Xianbei and Ren Jie in the north went south many times, which accelerated the downfall of the dynasty, directly led to the national subjugation of the Western Jin Dynasty and nearly 300 years of turmoil, and made China enter the Five Chaos period.
If Sima Yi, a lean man, knew that the family had fallen so fast because a stupid prince had led to a fight in the palace, I'm afraid he could only sigh his fate.