Cao Yu 曹宇

Cao Yu's courtesy name was Pengzu. He was one of the twenty-five sons of Emperor Wu, Cao Cao, born to Lady Huan; Cao Chong, Prince Ai of Deng, and Cao Ju, Prince of Pengcheng, were born of the same mother. In the 16th year of Jian'an (211) he was enfeoffed as Marquis of a Chief District, and in the 22nd year (217) he was re-enfeoffed as Marquis of Luyang. In the 2nd year of Huangchu (221) his rank was raised to duke, in the 3rd year (222) he became Prince of Xiapi, and in the 5th year (224) his fief was changed to Shanfu County. In the 6th year of Taihe (232) he was re-enfeoffed as Prince of Yan. Records, Wei 20 §2 · 18

Emperor Ming, Cao Rui, had lived with Cao Yu in childhood and so always held him in special affection, and on ascending the throne he bestowed favour and gifts on him unlike those given to the other princes. Cao Yu was summoned to court in the 3rd year of Qinglong (235), returned to Ye in the 1st year of Jingchu (237), and in the summer of the 2nd year (238) was summoned again and came to the capital. Records, Wei 20 §18–19

In the 12th month of the 2nd year of Jingchu (early 239 CE), when Emperor Ming's illness became critical, he appointed Cao Yu General-in-Chief and entrusted him with affairs after his death. Emperor Ming intended to have him assist in the government together with Xiahou Xian, General Who Leads the Army, Cao Shuang, General of the Martial Guard, Cao Zhao (曹肇), Colonel of Garrison Cavalry, and Qin Lang, General of Valiant Cavalry, but Cao Yu, being respectful and good by nature, sincerely and firmly declined. When Emperor Ming called Liu Fang and Sun Zi into his bedchamber and asked whether the Prince of Yan truly meant it, the two answered that it was because the Prince of Yan truly knew himself unable to bear so great a task. Records, Wei 20 §19Records, Wei 14 §151

When Emperor Ming asked whether Cao Shuang could take Cao Yu's place, Liu Fang and Sun Zi agreed, and urged that the Grand Commandant Sima Yi be summoned at once to hold together the imperial house. Emperor Ming in the end summoned Cao Shuang alone to receive the edict's command together with Liu Fang and Sun Zi, and dismissed Cao Yu, Xiahou Xian, Cao Zhao (曹肇) and Qin Lang from office. Cao Yu's biography says that four days after receiving the appointment Cao Yu firmly declined, the emperor also changed his mind, and he was finally removed from office; the Annals of Emperor Ming say that Cao Yu, Prince of Yan, was made General-in-Chief, was dismissed on the jiashen day, and was replaced by Cao Shuang. Records, Wei 14 §152–153Records, Wei 20 §19Records, Wei 3 §63

Cao Yu returned to Ye in the summer of the 3rd year of Jingchu (239). During the Jingchu, Zhengyuan and Jingyuan eras his fief was enlarged several times, reaching 5,500 households together with the earlier grants. His son Cao Huan, Duke of Changdao District, entered to continue the main line of succession: he had been enfeoffed as Duke of Changdao District in Anci County in the 3rd year of Ganlu (258), and when Cao Mao, Duke of Gaogui District, died, he was welcomed by the decision of the high ministers and ascended the imperial throne. Records, Wei 20 §19Records, Wei 4 §113

In the 11th month of the 1st year of Jingyuan (260), when the Prince of Yan submitted a memorial congratulating the emperor on the winter solstice and styled himself a subject, an edict was issued saying that in ancient times there were those whom the king did not treat as subjects, that he should not style himself a subject in his memorials, and that the matter should be handled as fittingly as possible. The officials in charge proposed that the Prince of Yan's memorials follow the old form; that edicts inquiring after him be worded 'The Emperor respectfully inquires after the attendants of the Great Prince'; that, except in matters of assisting at the sacrifices of the ancestral temple, the prince's personal name not be used; and that officials and commoners not violate the prince's taboo name. Records, Wei 4 §115–119

In the assessment of the volume in which Cao Yu appears, Chen Shou lamented the abuses of the system, saying that the princes and dukes of Wei had only the name of their fiefs without the substance of their altars of state, that they were cut off by prohibitions and surveillance as if they were in prison, and that, their ranks and titles never being fixed, their fiefs changed year after year. Records, Wei 20 §93