Cao Mao

Biography

Family Background and Early Life Cao Mao was the son of Cao Lin, Prince Ding of Donghai, and the grandson of Cao Pi, Emperor Wen of Cao Wei. In 244, the fifth year of Zhengshi, at only three years old, Cao Mao was enfeoffed as Duke of Gaogui District in Tan County. Little is recorded of his childhood beyond his life as a member of the imperial clan. The Records of the Three Kingdoms identifies him as the grandson of Emperor Wen and the son of Cao Lin and records his enfeoffment in Zhengshi 5. Cao Mao was described as intelligent and studious from childhood. His grandfather Cao Pi had been a famous writer and statesman, and the Cao family possessed a strong literary tradition. Cao Mao became well versed in classical learning and skilled at poetry and prose, abilities that later appeared in his debates at the National University and in literary gatherings with ministers. ### Accession and Early Rule In 254, the sixth year of Jiaping, General-in-Chief Sima Shi deposed Cao Fang. Sima Shi initially wanted to install Cao Ju, Prince of Pengcheng and a son of Cao Cao. Empress Dowager Guo objected that Cao Ju was an uncle of her late husband by ritual status; if he became emperor, her own position as empress dowager would no longer be appropriate. She instead proposed Cao Mao, grandson of Cao Pi, as successor and as heir to his childless uncle Cao Rui, Emperor Ming. Sima Shi ultimately accepted this choice. On the fifth day of the tenth month, November 2, 254, Cao Mao arrived in Luoyang. Civil and military officials knelt to receive him south of the Western Side Gate. Cao Mao descended from his carriage and attempted to return their salute. A ceremonial official told him that he did not need to bow to them, to which Cao Mao replied: “I too am still a subject.” At the Gate Where Carriages Stop he again descended. Attendants told him that precedent required him to ride into the palace, but Cao Mao replied: “I have been summoned by the empress dowager and do not yet know what she intends.” He then walked to the Eastern Hall of the Taiji Palace to meet Empress Dowager Guo and later that day formally ascended the throne in the Front Hall. The source also records that during the accession ceremony Cao Mao received the seal in a manner considered careless and walked with his feet raised high. Sima Shi was displeased when he heard of this. The Book of Jin states that the emperor received the seal indolently and lifted his steps high, causing Sima Shi concern. The episode was later interpreted as an early sign of tension between Cao Mao and the Sima clan. After taking the throne, Cao Mao ordered reductions in palace expenditure and halted production of luxury crafts. He also sent Palace Attendants to inspect the provinces, observe conditions among the people, and investigate officials who neglected duty, showing a desire for active government. On November 6, 254, the court assessed the contributions of ministers during the deposition and succession and distributed rewards according to merit. ### Struggle with Sima Zhao In the first month of 255, Sima Shi died at Xuchang after the campaign against the revolt of Guanqiu Jian and Wen Qin. Cao Mao tried to exploit the opportunity. He ordered Sima Zhao to remain at Xuchang while Director of the Secretariat Fu Gu led the main army back to Luoyang, hoping thereby to recover control of the troops. Sima Zhao ignored the order. Following the advice of Fu Gu and Zhong Hui, he instead marched directly to Luoyang. On the fifth day of the second month, March 29, 255, Cao Mao was forced to appoint Sima Zhao General-in-Chief, Palace Attendant, commander of all military affairs inside and outside the capital, and Recorder of the Affairs of the Secretariat, with authority to assist government and the privilege of entering the palace armed and wearing shoes. Sima Zhao formally declined some of these honors. Sima Zhao's control over the imperial house then grew stronger. In 257, the second year of Ganlu, when he personally campaigned against Zhuge Dan's rebellion, he compelled Cao Mao and Empress Dowager Guo to accompany the army, using the imperial presence to suppress opposition. Cao Mao remained emperor in name, but political power had passed entirely to Sima Zhao. ### Debates at the National University and the “Submerged Dragon” Poem Despite his political situation, Cao Mao continued to study. In the fourth month of 256, the third year of Zhengyuan, he personally visited the National University and debated the meanings of the Book of Changes and the Book of Documents with the Erudites, offering a number of his own interpretations. He often discussed literature in the Eastern Hall of the Taiji Palace with Sima Wang, Wang Shen, Pei Xiu, and Zhong Hui. He called Pei Xiu “the elder of the Confucian forest” and Wang Shen “the gentleman of literary records.” Cao Mao was impatient and expected officials to arrive immediately when summoned. Pei Xiu and others served within the palace and could come quickly, but Sima Wang worked outside and could not. Cao Mao therefore gave him a fast pursuit carriage and five Huben guards so that he could attend literary discussions without delay. On March 22, 256, Cao Mao held a banquet in the Eastern Hall and discussed the merits of former rulers with Palace Attendant Xun Yi, Secretariat officials Cui Zan, Yuan Liang, Zhong Yu, Palace Gentleman and Secretariat Director Yu Song, and others. Cao Mao strongly admired Shao Kang, restorer of the Xia, and argued that Shao Kang's virtue exceeded that of Liu Bang, Emperor Gaozu of Han. Xun Yi and the others favored Liu Bang, but Cao Mao argued his position in detail from virtue, achievement, and historical circumstances. The discussion continued for two days and, according to the source, the ministers were eventually persuaded. Zhong Hui recorded the debate in detail for later generations. In 259, the fourth year of Ganlu, Cao Mao composed a poem about a “submerged dragon,” using a dragon trapped at the bottom of a well as a metaphor for himself under Sima control. The poem says in the source: “Alas, the dragon is trapped and cannot leap into the deep; above it cannot fly to the heavenly river, below it cannot appear in the field. Coiled at the bottom of the well, it watches loaches and eels dance before it. Hiding teeth and folding claws—alas, I am the same.” When Sima Zhao learned of the poem he became more wary, and the conflict between ruler and minister intensified. ### Attack on Sima Zhao and Death In the fifth month of 260, Cao Mao summoned Palace Attendant Wang Shen, Secretariat official Wang Jing, and Cavalier in Regular Attendance Wang Ye. He declared: “Sima Zhao's intentions are known to every passerby. I cannot sit and accept deposition and humiliation. Today I will go out with you and attack him myself.” Wang Jing warned that the Sima family had held power for a long time, that the court and the regions were committed to it, and that the palace guard was weak. He urged the emperor to reconsider lest an attempt to cure the disease make it worse. Cao Mao nevertheless remained determined. Ignoring the opposition of Empress Dowager Guo and other officials, he led more than three hundred palace attendants out with drums and shouts to attack Sima Zhao. Wang Shen and Wang Ye left first and informed Sima Zhao. Sima Zhao immediately sent troops into the palace. The two sides met near the Eastern Gate Where Carriages Stop. Central Protector Jia Chong led soldiers to confront Cao Mao below the Southern Gate. Jia Chong ordered Cheng Ji to kill the emperor. Cheng Ji thrust a sword through Cao Mao's chest; Cao Mao died on his carriage, blood covering the ground. He was nineteen. Afterward, Sima Zhao issued an edict in Empress Dowager Guo's name declaring that the Duke of Gaogui District had acted rebelliously and brought disaster on himself and should, following the precedent of the deposed King of Changyi under Han, be buried with commoner rites. At the request of Sima Fu, Sima Zhao's uncle, and other senior officials, Cao Mao was instead buried with princely rites about thirty li northwest of Luoyang at the bank of the Chanjian. The funeral procession had only a few carriages and no ceremonial banners. People gathered to watch and said: “That is the emperor who was killed the other day.” Some covered their faces and wept uncontrollably. With public anger widespread, twenty days after the killing Sima Zhao placed full responsibility on Cheng Ji, accusing him of killing Cao Mao contrary to orders, and executed Cheng Ji's three clans for high treason. Cao Huan was then installed as emperor.

His Family, His Title and His Accession

Cao Mao, courtesy name Yanshi, was a man of Qiao county in the Pei state, grandson of the cultured emperor Cao Pi and son of Cao Lin, prince of Donghai, and was early enfeoffed as duke of Gaogui of the district of Tan, the title by which later ages usually called him. In the fifth year of Zhengshi, 244, he was enfeoffed as duke of Gaogui; and in the sixth year of Jiaping, 254, Sima Shi having deposed Cao Fang, the prince of Qi, he, by the Comprehensive Mirror, summoned the ministers with the empress dowager's order, on the ground that the emperor was "lewd beyond measure and familiar with actors and singers, unfit to inherit the heavenly succession," and none of the ministers dared oppose it, so that the imperial seals were taken and he was sent back to Qi as a prince. Sima Shi sent Guo Zhi into the palace to inform the empress dowager, who was sitting facing the emperor; and Guo Zhi told the emperor that the general-in-chief meant to depose him and set up the prince of Pengcheng, Ju, at which the emperor rose and went out, and the empress dowager was displeased. Guo Zhi said that the empress dowager had a son whom she could not teach, and that the general-in-chief's mind was made up with troops outside against any change, so that she should but comply; and when she said she wished to see the general-in-chief and speak her mind, he answered that he could not be seen and that the seals should be taken quickly, at which her will broke and she had the attendant take the seals and lay them by her seat. Afterwards Sima Shi sent again for the seals, and the empress dowager said that the prince of Pengcheng was her own father's younger brother, and where would she be if he were set up, and that the emperor Ming could not be left without a successor, the duke of Gaogui being a grandson of the cultured emperor and, in the junior line, son of the emperor Ming's younger brother, so that by ritual a junior branch might carry on the senior, and the matter should be carefully considered; and on the day dingchou Sima Shi summoned the ministers again and showed them her order, and it was settled to welcome the duke of Gaogui, Cao Mao, from Yuancheng. On the fifth day of the tenth month, 2 November 254, Cao Mao came to Luoyang, and the civil and military officials bowed to him south of the western side gate; and Cao Mao stepping down from his carriage meant to return their bow, and the master of ceremonies told him that by rule he did not bow, but Cao Mao said that he too was a subject and bowed in return. Reaching the gate where carriages stop he stepped down again, and those about him saying that by old practice he should ride in, he answered that he had been summoned by the empress dowager and did not know for what, and so walked to the eastern hall of the Taiji palace and saw the empress dowager, and that same day took the throne in the front hall.

The Zheng Yuan Period and the Usurpation of Sima Zhao

In the second year of Zhengyuan, 255, Sima Shi died, and Cao Mao sought to recover the military power but failed. By the History of Jin, Sima Zhao on the advice of the president Fu Gu and Zhong Hui led his army straight back to Luoyang and was advanced to be general-in-chief with the title of palace attendant, commander of all armies within and without, charged with the business of the secretariat and regent, with the right to wear his sword and shoes in the hall, though he declined and would not accept it; and on the fifth day of the second month, 29 March 255, Cao Mao was obliged to confirm him in those offices, so that the government of Wei passed into Sima Zhao's hands. Cao Mao would often hold discussions on letters in the eastern hall of the Taiji palace with the guard general Sima Wang, the palace attendant Wang Shen, the cavalier attendant in ordinary Pei Xiu and the yellow-gate vice-director Zhong Hui, calling Pei Xiu the elder of the Confucian grove and Wang Shen the sir of books and documents, while Sima Wang and Zhong Hui had titles of their own; and being impatient, so that when he summoned a minister he must come at once, since Pei Xiu and the others held inner offices they came in time, but Sima Wang being without, he was specially given a pursuit carriage and five tiger guards, and "whenever there was a gathering Wang galloped to arrive." In the second month of the first year of Ganlu, 256, Cao Mao feasted his ministers in the eastern hall and discussed rites with the palace attendant Xun Yi, the ministers Cui Zan, Yuan Liang and Zhong Yu and the palace attendant and president of the secretariat Yu Song, and so came to the comparison of emperors. Admiring Shao Kang of Xia, he asked Xun Yi and the rest which of the two, Shao Kang who gathered the people of Xia and restored the work of Yu, or the founder of Han who rose from the fields and drove the heroes and cut down Qin and Xiang, should be held the greater in merit and virtue; and Xun Yi and the rest answered that the great vessel of the realm is given by heaven to the sage whose virtue answers the time, and that there was a difference between building anew and following on, so that though Shao Kang's merit and virtue were fine he was but a restorer of the middle, to be ranked with the founder of the Later Han, while the founder of Han they thought the greater. But Cao Mao said that of emperors ancient and modern merit, virtue, words and deeds had each their high and low, and that it did not follow that founders were always the greater and successors the less; that Shao Kang, born after the extinction of his house and reduced to the servitude of a prince, had gone through hardship and barely escaped with his life, yet could spread his virtue and begin his plans, destroy the houses of Guo and Ge and restore the work of Yu, sacrificing to Xia and matching heaven, which only the highest virtue and the widest benevolence could achieve; whereas the founder of Han, riding the collapse of the age and relying on a moment's power, had won by mere wit and strength, his conduct often breaking the sages' rule, endangering his parents as a son, imprisoning a worthy minister as a lord and unable to protect his son as a father, so that after his death the altars of state all but fell, and had he and Shao Kang changed times he might not have restored the work of the great Yu; and therefore Shao Kang should be set above the founder of Han. The next day Xun Yi and Yuan Liang argued that in the three dynasties, with the land divided among princes, decline came slowly and men could be won by virtue but not subdued by force, whereas from the Warring States the strong swallowed the weak and, casting off morality, used wit and arms, so that the ruin of Qin could be contested by force; and that Shao Kang, who spread virtue, was the flower of the benevolent, and the founder of Han, who used force, the flower of the wise, and that benevolence and wisdom being different the two were emperors of different kinds, with Shao Kang the greater. Cui Zan, Zhong Yu and Yu Song said that Shao Kang, though he had accumulated virtue, inherited the blessing of the great Yu with the aid of the Yu and Reng within and of Mi and Ai without, while the founder of Han rose from common cloth and led a rabble to the imperial work, so that in virtue Shao Kang was the greater, in merit the founder, in means Shao Kang had the easier and in time the founder the harder. Cao Mao then set out the principle that the highest is to establish virtue and the next to establish merit, that the benevolent must have courage and to punish a tyrant one must use arms, so that Shao Kang's martial majesty need not be below the founder's, and that only because the books of Xia were lost and the old records broken was his merit and beauty unrecorded; at which all the ministers were pleased and convinced. Yu Song asked that his words be written down to make Shao Kang's name known to later ages, and Cao Mao, saying modestly that his learning was not wide and his knowledge shallow, had Zhong Hui put the discussion in order.

His Disputations in the Imperial College and the Poem of the Hidden Dragon

In the fourth month of the first year of Ganlu Cao Mao visited the imperial college and asked the scholars the meaning of the Changes and the difference of the three versions, and the doctor of the Changes, Chunyu Jun, answered that Bao Xi made the eight trigrams from the plan of Suiren and Shennong developed them into sixty-four, that the Changes therefore meant change, that the Xia called them the Lian Shan because they were like a mountain breathing out and in and joining heaven and earth, and the Shang the Gui Zang because all things are hidden within them. Cao Mao asked further why, since Confucius made the commentaries and Zheng Xuan the notes, the commentaries were not joined to the text while the notes were; and Chunyu Jun answered that Zheng Xuan joined them to make it easier for students; and Cao Mao asking why then Confucius had not joined them if it eased study, he answered that Confucius feared confusion with King Wen, and that the sage took not joining as his humility; and when Cao Mao asked whether then only Zheng Xuan was not humble, Chunyu Jun could not answer. Passing to the Documents, he asked whether Zheng Xuan's reading of "examining antiquity like heaven," that Yao was like heaven, or Wang Su's, that Yao followed the ancient way, were right; and the doctor Yu Jun answered that the old scholars differed and that by the Hongfan, where three diviners differ follow two, and since Jia Kui, Ma Rong and Wang Su all took it as following the ancient way, Wang Su's reading was the better. Cao Mao, citing Confucius that only heaven is great and only Yao matched it, held that Yao's greatness lay in matching heaven and that following the ancient way was not his highest, and he pressed the doctors on the four mountains' recommending Gun, asking whether the sage's discernment could be incomplete; and Yu Jun answering that even the great sage had his limits and that Yao had after all changed and given the throne to Shun and so was a sage, Cao Mao said that to have both beginning and end was the mark of the sage and that one who could not begin was no sage. On the Book of Rites he asked the meaning of the highest being to establish virtue and the next to attend to requital, and the doctor Ma Zhao answered that the highest was the three sovereigns and five emperors who transformed the people by virtue and the next the three kings who governed by rites; and Cao Mao asking whether the difference in their transforming came of the rulers' quality or of the times, Ma Zhao answered that it came of the times being simple or refined. In the first month of the fourth year of Ganlu two yellow dragons appeared in a well at Ningling, dragons having also appeared in wells at Dunqiu, Guanjun and Yangxia; and the ministers holding it auspicious, Cao Mao said that the dragon was the virtue of a ruler, that it was neither in heaven above nor in the fields below but bowed again and again in a well, which was no good omen, and wrote the Poem of the Hidden Dragon to mock himself, at which Sima Zhao seeing it hated him. On the sixth day of the fifth month of the fifth year of Ganlu, 1 June 260, Cao Mao, seeing his authority daily departing and unable to bear his indignation, summoned the palace attendant Wang Shen, the minister Wang Jing and the cavalier attendant in ordinary Wang Ye, and said that Sima Zhao's mind was known to every passer-by, that he could not sit and suffer deposition and disgrace, and that he would go out with them that day to attack him. Wang Jing warned him with the example of the duke of Lu who could not bear the Ji family and fled his state to be laughed at by the world, saying that the power had long been in that house and that the palace guards were few and weak and he had nothing to rely on; but Cao Mao threw down the yellow silk edict from his breast and said the thing was decided, that even death was not to be feared, much less that he need not die; and so he went in to tell the empress dowager. Wang Shen and Wang Ye ran to inform Sima Zhao and called Wang Jing to go with them, but he would not.

The Affair at the Southern Gate and His Murder

On the seventh day of the fifth month of the fifth year of Ganlu, 2 June 260, Cao Mao, learning that his plan had leaked, drew his sword, mounted his carriage and led the guards, servants and grooms of the palace out with shouts. Sima Zhao's younger brother, the cavalry colonel Sima Zhou, met him at the eastern carriage gate and was shouted at, so that his men fled; and the guard general Jia Chong coming in from without met the emperor in arms below the southern gate, the emperor using his own sword, so that the troops were inclined to fall back. The cavalry overseer Cheng Cui's younger brother, the household officer Cheng Ji, asked Jia Chong what was to be done in such an extremity, and Jia Chong said sharply that the duke of Sima kept them and fed them precisely for this day and that nothing need be asked; and Cheng Ji at once thrust forward with his halberd and killed the emperor, who fell beside the carriage at nineteen. Sima Zhao called the hundred officials to consider the matter, and the president Chen Tai, sent by his uncle Xun Yi in a carriage, was brought to a private room and asked how the world would judge him; and Chen Tai said that only by beheading Jia Chong at the waist could he somewhat answer to the world, and Sima Zhao told him to think of the next best, and Chen Tai said he could see only the first and not the next; and so the guilt was laid on Cheng Ji, who was beheaded with his brother and their three clans destroyed. Wang Jing, for not having informed against the emperor, was given to the commandant of justice and put to death, and at his execution, when he took leave of his mother, she, unchanged in countenance, smiled and said that no man can escape death and that she feared only to die in the wrong place, and that to die together so was no cause for regret; and when he was killed his former subordinate Xiang Xiong wept so that the whole market was moved. Afterwards the grand tutor Sima Fu, the general-in-chief Sima Zhao, the grand commandant Gao Rou and the minister of education Zheng Chong bowed their heads and memorialised that the duke of Gaogui had been perverse and impious and brought ruin on himself, and that by the precedent of the prince of Changyi of Han, deposed for crime, he should be buried with the rites of a commoner; yet that knowing the empress dowager's excessive kindness they could not bear it and thought he might be graciously buried with the rites of a prince, to which the empress dowager agreed.

The Appointments of the Ganlu Years and the Rites after His Death

In the Ganlu years the authority of the Sima house was further strengthened in the structure of office: on the day gengwu of the eighth month the court made the general-in-chief Sima Zhao grand commander-in-chief, so that in memorialising he need not give his name and might carry the yellow battle-axe; on the day guiyou the grand commandant Sima Fu was made grand tutor; in the ninth month the minister of education Gao Rou was made grand commandant; and in the tenth month of winter the minister of works Zheng Chong was made minister of education and the vice-president of the left of the secretariat Lu Yu minister of works. After Cao Mao's murder the discussion at court first meant to bury him with the rites of a commoner, by the precedent of the prince of Changyi of Han deposed for crime; but the grand tutor Sima Fu, the general-in-chief Sima Zhao, the grand commandant Gao Rou and the minister of education Zheng Chong bowed their heads and memorialised that knowing the empress dowager's excessive kindness they could not bear it and thought he might be graciously buried with the rites of a prince, to which the empress dowager agreed, and so he was buried with a prince's rites; while the minister Wang Jing, who would not inform against him, was given to the commandant of justice and put to death.

Major Activities

Literary Contribution Cao Mao was skilled in poetry and prose and was known as a cultivated young emperor. Sima Shi once asked Zhong Hui about Cao Mao's abilities. Zhong Hui replied: “In letters he equals Chen Si; in martial ability he resembles Taizu,” comparing his literary talent to Cao Zhi and his martial qualities to Cao Cao. His best-known surviving poem used a dragon trapped in a well to symbolize his position under Sima Zhao. The poem became a lasting symbol of Cao Mao's refusal to accept puppet status and his willingness to resist. Cao Mao also frequently discussed literature with Sima Wang, Wang Shen, Pei Xiu, and Zhong Hui in the Eastern Hall of the Taiji Palace and exchanged judgments on poetry and prose. His nicknames for Pei Xiu and Wang Shen show how closely he interacted with literary officials. ### Classical Learning Cao Mao was deeply versed in classical studies and repeatedly visited the National University to debate the Book of Changes and the Book of Documents with the Erudites. In 256 he questioned scholars on textual meanings and presented original interpretations. At the March 22 banquet of the same year, he debated with ministers over the comparative merits of Shao Kang of Xia and Liu Bang, Emperor Gaozu of Han. Cao Mao argued at length that Shao Kang was superior, comparing virtue, achievements, and historical circumstances, and ultimately persuaded the ministers according to the source. Zhong Hui's record of the discussion became an important source for Cao Mao's intellectual outlook. ### Political Activity After taking the throne, Cao Mao reduced palace expenses, halted production of luxury objects, and sent Palace Attendants to inspect local conditions and official failures. These measures reflected an intention to govern actively despite his lack of real power. After Sima Shi's death in 255, Cao Mao attempted to recover the army by ordering Sima Zhao to remain at Xuchang while Fu Gu brought the troops back to Luoyang. Sima Zhao instead marched to the capital, and Cao Mao was forced to grant him the office of General-in-Chief. Political power thereafter rested completely with Sima Zhao. In 260, unwilling to submit to eventual deposition, Cao Mao summoned trusted officials and planned to kill Sima Zhao. After the plan was revealed, he led more than three hundred palace attendants out to attack and was killed. The source presents this as his most tragic political act and one of the best-known episodes of the late Three Kingdoms period. ### Artistic Talent The source also describes Cao Mao as a capable painter and a talented practitioner of music, chess, calligraphy, and painting. Although no paintings survive, historical accounts remembered his ability in the visual arts.

His Measures in Office and His Learning

On his accession Cao Mao decreed a reduction of palace expenditure and a stop to the making of luxurious articles, and sent palace attendants to tour the four quarters to learn the people's condition and to check the failures of officials. He was deeply versed in the classics and several times visited the imperial college to dispute points of the Changes, the Documents and the Book of Rites with the doctors, offering opinions differing from the old scholars, as that since only heaven is great and only Yao matched it, Yao's greatness lay in matching heaven and not in following the ancient way, and that only the sage has both beginning and end, so that one who cannot begin is no sage, driving the doctors to silence by his repeated questioning. By the bibliographic treatise of the History of Sui there were in the Liang three volumes of the duke of Gaogui's sounds and readings of the Zuo Commentary, afterwards lost; and Yan Yu, discussing the origins of poetic forms, says that the nine-character line began with the duke of Gaogui, so that he had some part in literary invention as well.

The Judgements of Later Ages

Later ages judged his death to have been a case of firmness losing, one writer holding that the fortunes of a ruler may be won by firm resolve or lost by patience, and that while Emperor Xuan of Han's destruction of Huo Yu, Emperor He's of Dou Xian, Emperor Huan's of Liang Ji and Emperor Xiaozhuang of Wei's of Erzhu Rong were firmness that succeeded, the duke of Lu's attack on the Ji family, the duke of Qi's plot against Tian Chang, the duke of Gaogui's attack on Sima Zhao, Emperor Yuan of Jin's campaign against Wang Dun, Emperor Wenzong of Tang's plot against the eunuchs and the emperor Yin of Han's killing of Guo Wei were firmness that failed. Others praised his purpose highly, holding that in classical learning and letters he had his models, that he attended to government and kept Shao Kang in mind, and that he was a good ruler rare since the three dynasties, and that his resolve to attack Sima Zhao showed him no less than a hero, citing the duke of Chu's attack on Dou Jiao, the duke of Wu's on Sun Chen and the emperor Wu of Zhou's on Yuwen Hu as instances of daring that succeeded, and lamenting that rulers of later ages, frightened by the examples of the duke of Lu and the duke of Gaogui, bore and endured until they bred great calamities; and they held that his words that even death was not to be feared were so spirited that a thousand years after they still breathe. Of his learning one said that the histories call him quick and clever from youth and fond of questioning and of words, as his disputations in the college showed, and that while the rulers of declining ages often had literary gifts, none was so deep in the classics as the duke of Gaogui; though another mocked his questions as shallow and beside the great principles, a showing off of talent without the secret reticence that would have kept him safe. His murder was cited again and again: when Yu Chun quarrelled with Jia Chong at a banquet and cried that all the disorder of the realm came from him alone, and Jia Chong answered that he had served two sovereigns and pacified Ba and Shu, Yu Chun asked him where the duke of Gaogui was, at which the company broke up; when Sun Hao surrendered to Jin, Jia Chong asking him why he had liked to flay men's faces, Sun Hao answered that he thought the punishment fit regicides and the disloyal; and when Wang Dao recounted to Emperor Ming of Jin how the dynasty had come by the realm, and told of the affair of the duke of Gaogui at the end of the prince of Wen's life, the emperor covered his face on the couch and asked how the dynasty's fortune could long endure.

Personal Relations

• Grandfather: Cao Pi, Emperor Wen of Cao Wei
• Father: Cao Lin, Prince Ding of Donghai
• Uncle: Cao Rui, Emperor Ming of Cao Wei, whose dynastic line Cao Mao continued
• Empress: Empress Bian, daughter of Bian Long, made empress in 255
• Descendant: Cao Ba, painter under Emperor Xuanzong of Tang, praised by Du Fu in “Song of a Painting” - Sima Wang: frequently discussed literature with Cao Mao and received a fast carriage to facilitate palace attendance
• Wang Shen: called “the gentleman of literary records” by Cao Mao; later informed against him
• Pei Xiu: called “the elder of the Confucian forest” by Cao Mao
• Zhong Hui: frequently discussed literature with Cao Mao and recorded his debates with ministers - Sima Shi: General-in-Chief who deposed Cao Fang and installed Cao Mao; Cao Mao's demeanor toward him was described as proud
• Sima Zhao: effective ruler during Cao Mao's reign; target of the submerged-dragon poem and of Cao Mao's final attack
• Empress Dowager Guo: advocated Cao Mao's accession but opposed his final attempt against Sima Zhao
• Wang Jing: warned Cao Mao against attacking Sima Zhao and was later executed for loyalty to him - Cheng Ji: killer of Cao Mao under Jia Chong's direction; later executed with his three clans
• Jia Chong: Central Protector who ordered Cheng Ji to kill Cao Mao
• Wang Shen and Wang Ye: officials who informed Sima Zhao of Cao Mao's plan

Historical Assessment

Wei and Jin Periods - Chen Shou, in his treatment of the three young emperors in the Records of the Three Kingdoms, expressed sympathy for Cao Mao's fate, describing him as precociously talented, fond of inquiry, and appreciative of refined speech, while also criticizing him as impetuous and angry and saying he brought disaster upon himself.

• Zhong Hui praised Cao Mao with the phrase: “In letters he equals Chen Si; in martial ability he resembles Taizu.”
• After Cao Mao's death, Sima Zhao initially denounced him in Empress Dowager Guo's name, but under public pressure allowed a princely burial and executed Cheng Ji's three clans. ### Eastern Jin and Northern and Southern Dynasties - Xi Zuochi's Spring and Autumn of Han and Jin gives a detailed account of Cao Mao's attack on Sima Zhao and treats his courage favorably, presenting him as honorable despite defeat.
• Pei Songzhi's annotations to the Records of the Three Kingdoms cite numerous accounts concerning Cao Mao and recognize his learning.
• The source attributes to Cui Hong of Northern Wei an assessment that Cao Mao was among the unusually capable members of the Cao imperial house but was born at an unfortunate time. ### Tang and Song Periods - Liu Zhiji, in Shitong, treated Sima Zhao's killing of the ruler as the act of a rebellious minister and praised Cao Mao's integrity even though his resistance exceeded his actual power.
• Sima Guang's Comprehensive Mirror in Aid of Governance gives a detailed account of Cao Mao's life and final action and presents his refusal to remain a puppet with sympathy.
• Hu Sansheng, in his annotations to the Comprehensive Mirror, wrote that Cao Mao faced a dangerous age while still very young; although gifted, he ultimately could not escape disaster. ### Modern Assessments - Lü Simian, in Informal Talks on the Three Kingdoms, regarded Cao Mao as an emperor with moral courage who resisted Sima domination and was honorable in defeat.
• Modern scholarship generally treats Cao Mao's death as marking the effective end of Cao Wei imperial authority and a crucial turning point in the Wei-Jin transfer.
• Some scholars emphasize that the tragedy lay in his historical timing: Cao Wei power was already hollow, so his resistance, however brave, was almost certain to fail.