In 220, after Cao Cao successfully captured Guan Yu and captured Jingzhou, he made Sun Quan a hussar general and pastor of Jingzhou. Sun Quan's courtiers came to pay tribute, pledging allegiance and suggesting that Cao Cao replace the Eastern Han Dynasty and proclaim himself emperor of Wei. Faced with this decision, Cao Cao did not rush to adopt it, but chose to show Sun Quan's letter to his internal and external courtiers to seek their opinions. Cao Cao once said: "Does this kid want to replace him? Nevertheless, Cao Cao's close ministers also offered to support Sun Quan's proposal. However, Cao Cao himself did not rush to usurp Han as emperor, but stuck to his own beliefs, saying: "If destiny destined me to become a monarch like King Wen of Zhou, it would naturally come true." Finally, in the first month of 220 AD, Cao Cao returned to Luoyang, but in October of the same year, he died of illness in Luoyang at the age of sixty-six. After Cao Pi succeeded to the throne, he replaced the Eastern Han Dynasty, forcing Liu Xie, the emperor of the Eastern Han Dynasty, to abdicate, ascend the throne himself, establish the state of Wei, and posthumously honor Cao Cao as Emperor Wu, with the temple name Taizu. However, one question remains: why did Cao Cao not dare to usurp Han as emperor, while his son Cao Pi dared to do so?
The answer to this question lies in the fundamentally different historical backgrounds of Cao Cao and Cao Pi. Cao Cao lived in a time when the Eastern Han Dynasty was in full swing, and although the Eastern Han Dynasty had declined, there were still many people who supported the imperial family, such as Liu Yu, Kong Rong, Xun Yu, Liu Bei, Zhuge Liang, and Guan Yu, all with loyalty to the Eastern Han Dynasty. Whether it was benevolent people or ordinary people, there were a considerable number of people who supported the Eastern Han royal family, which was also an important reason why Liu Bei was able to gain a foothold. In addition, Yuan Shu proclaimed himself emperor in the second year of Jian'an (197 AD), but was soon defeated by a joint attack by Sun Ce, Lü Bu, and Cao Cao. Therefore, Cao Cao personally experienced the lesson of Yuan Shu's failure to claim the emperor, which made him deeply understand the risks of becoming emperor. Therefore, Cao Cao was not in a hurry to usurp the Han Dynasty to stand on his own, and he still had a firm commitment to continuing his allegiance to the Eastern Han Dynasty.
The situation was different for Cao Pi, who lived in a time that had changed dramatically, and people's loyalty began to shift from the Eastern Han dynasty to Cao Wei. Before the establishment of Cao Wei, the northern Central Plains experienced a long period of war, and various separatist forces competed for the Central Plains, resulting in Liu Xie, the emperor of the Eastern Han Dynasty, suffering from it, and the people were exhausted. At this moment, Cao Cao came to prominence, he unified the Central Plains, eliminated Yuan Shu, Yuan Shao, Lü Bu, Liu Biao, Ma Chao, Han Sui and other separatist forces, revived the Central Plains, carried out land settlements, water conservancy projects, rewarded farming, developed handicrafts, resettled displaced people, and implemented "rent modulation", which restored vitality to the Central Plains. As a result, Cao Pi believed that popular sentiment had gradually shifted to Cao Wei, which provided a solid foundation for him to usurp Han and claim the throne. In Cao Pi's view, people's identification with Cao Wei had gradually increased, while loyalty to the Eastern Han dynasty was declining. This is also where Cao Pi's confidence to dare to claim the title of emperor lies.
In addition, Cao Pi had another important factor that prompted him to rush to the throne as emperor. He needs to build his prestige and consolidate his dominance. Compared to Cao Cao's achievements in unifying the Central Plains by force, Cao Pi also lacked sufficient prestige to influence the Wen Chens and military generals. Therefore, he quickly ascended the throne and became emperor, which was an effective means of enhancing his prestige. Once emperor, he could more easily confer knighthoods, thus achieving a reign of equal grace and power. On the other hand, Cao Cao had already established a solid foundation in the Central Plains, and his rule would not be threatened by not being called emperor.
To sum up, the reason why Cao Cao was not in a hurry to become emperor was because of the historical circumstances and risk considerations he was in. Correspondingly, Cao Pi was anxious to become emperor because the era in which he lived had changed significantly, and people's loyalty had shifted from the Eastern Han dynasty to Cao Wei, which provided him with the confidence and opportunity to become emperor. In addition, he needed to establish his prestige and consolidate his dominance, making the emperor an effective means of achieving this goal.