Sima Yao

Biography

Family Background and Early Life

Sima Yao was born in 362, the first year of the Longhe era of Emperor Ai of Jin. He was the sixth son of Sima Yu, Emperor Jianwen of Jin, and his mother was Li Lingrong. His grandfather was Sima Rui, Emperor Yuan of Jin and founding emperor of Eastern Jin. Sima Yu had seven sons, but his first five died young, leaving only Sima Yao and his full younger brother Sima Daozi. In 365, the third year of the Xingning era, after Sima Yi, Prince of Langya, succeeded to the throne, Sima Yu was transferred to the princedom of Langya, and four-year-old Sima Yao succeeded his father as Prince of Kuaiji.

In the eleventh month of 371, the sixth year of the Taihe era, the powerful military leader Huan Wen entered the capital with troops and carried out a palace coup. Acting through an order issued in the name of Empress Dowager Chongde Chu Suanzi, he deposed Sima Yi as Prince of Donghai and enthroned Sima Yu as Emperor Jianwen. Sima Yao thereby became an imperial prince.

From the establishment of Eastern Jin under Sima Rui south of the Yangtze, political authority had repeatedly fallen under the control of great aristocratic clans, forming the pattern known as aristocratic clan politics. By the reign of Emperor Jianwen Sima Yu, imperial weakness and aristocratic dominance had reached an extreme. Huan Wen controlled the central government so thoroughly that even Xie An treated him as a “lord”; the situation was summarized as “government rested with the Huan clan, while sacrifices alone belonged to me.” Huan Wen's ambition was to induce Emperor Jianwen to abdicate in his favor and transfer the Jin throne.

Accession as a Youth and the Initial Crisis

In the seventh month of 372, the second year of the Xian'an era, Emperor Jianwen became gravely ill. He designated Sima Yao, Prince of Kuaiji, as Crown Prince and left an edict stating, “Grand Marshal Wen should follow the precedent of the Duke of Zhou in acting as regent,” adding, “If the young son can be assisted, assist him; if not, you may take the throne yourself.” The Jin state was thus placed in extreme danger, for Huan Wen could have used the edict to seize the throne. Wang Tanzhi, an Attendant from the Taiyuan Wang clan, tore up the edict in Emperor Jianwen's presence. The emperor was compelled to revise it to read: “All affairs of the household and state shall be submitted to the Grand Marshal, following the precedents of Marquis Zhuge Wu and Chancellor Wang.” Emperor Jianwen died soon afterward.

Some ministers, intimidated by Huan Wen's power, proposed waiting for the Grand Marshal's decision. Wang Biaozhi, Vice Director of the Department of State Affairs from the Langya Wang clan, replied sternly: “When the Son of Heaven dies, the Crown Prince succeeds him. How can the Grand Marshal have any different role? If we first consult him in person, he will surely turn around and blame us.” Court discussion therefore settled on the Crown Prince's immediate enthronement as Emperor Xiaowu. Empress Dowager Chongde again cited Sima Yao's youth and ordered Huan Wen to act as regent following the precedent of the Duke of Zhou, but Wang Biaozhi returned the edict unopened and the order was never implemented.

Only three months after Emperor Xiaowu's accession, the Daoist Lu Song led three hundred followers into the palace precincts at Jiankang, seized weapons from the arsenal, and attempted to restore the Duke of Haixi. The disturbance was directed against Huan Wen and objectively strengthened resistance to him by the Wang and Xie clans. In the second month of 373, the first year of the Ningkang era, Huan Wen entered the capital from Gushu amid rumors that he intended to kill Wang and Xie leaders and seize the Jin throne. Wang Tanzhi, Xie An, and others prepared for confrontation. Huan Wen later fell ill but still demanded the Nine Bestowments; Wang Tanzhi, Xie An, and others delayed the process. Huan Wen died in the seventh month of that year, and the initial crisis of Emperor Xiaowu's reign passed without disaster.

Xie An's Government and the Battle of the Fei River

Although Huan Wen was dead, the structure of aristocratic clan politics remained. Because Emperor Xiaowu was young, and to prevent Huan Wen's younger brother Huan Chong and other members of the Qiao Commandery Huan clan from continuing to monopolize power, the Wang and Xie clans persuaded Empress Dowager Chongde to preside over court for a third time. Effective Eastern Jin authority thus remained in the hands of great clans, shifting gradually from the Huan clan of Qiao Commandery to the Xie clan of Chen Commandery.

In the fifth month of 375, the third year of Ningkang, Wang Tanzhi died and Xie An's power grew further. In the eighth month of the same year, Emperor Xiaowu married Wang Fahui, granddaughter of the noted Wang Meng of the Taiyuan Wang clan, and made her empress. His younger brother Sima Daozi, Prince of Langya, also married a grandniece of Wang Tanzhi.

On the first day of the first month of 376, the first year of Taiyuan, Emperor Xiaowu underwent the capping ceremony. Empress Dowager Chongde returned authority, and Xie An, as Director of the Secretariat and Supervisor of the Affairs of the Secretariat, became the effective chief minister. Xie An's greatest weakness was his lack of dependable military force. In 377, the second year of Taiyuan, he recommended his nephew Xie Xuan as Inspector of Yanzhou, stationed at Guangling. Two years later Xie Xuan concurrently became Inspector of Xuzhou and established his headquarters at Beifu. There he recruited Liu Laozhi, He Qian, Zhuge Kan, Gao Heng, Liu Gui, Tian Luo, Sun Wuzhong, and other capable commanders and integrated their largely refugee-based forces into the famous Beifu Army.

In the fourth month of 378, the third year of Taiyuan, Former Qin sent Fu Pi to attack Xiangyang. Huan Chong, Inspector of Jingzhou, resisted, while Emperor Xiaowu ordered Xie Xuan to mobilize manpower from Xuzhou, Yanzhou, and Qingzhou and sent He Qian, Administrator of Pengcheng, to maneuver through the Huai and Si region in support. He Qian's expedition was the Beifu Army's first combat action. By the first month of 379, Xiangyang had fallen and the Eastern Jin commander Zhu Xu was captured. Pengcheng and Xiapi subsequently passed to Former Qin, placing Jiankang in danger. In the sixth month of 379, the Beifu Army defeated Qin forces at Junchuan, drove Former Qin north of the Huai, and relieved the emergency around Jiankang.

In the eighth month of 383, the eighth year of Taiyuan, the Former Qin ruler Fu Jian ordered a massive invasion of Jin and the Battle of the Fei River began. Fu Jian personally led what the source describes as 600,000 infantry, 270,000 cavalry, and 30,000 imperial guards, a total force of 900,000, south from Chang'an. Confident of victory, he declared: “If all my soldiers cast their horsewhips into the river, they would be enough to stop its flow.” Eastern Jin had only about 80,000 men to resist. Under chief minister Xie An's direction, Xie Shi served as commander-in-chief, Xie Xuan led the vanguard, and Liu Laozhi formed the main striking force.

During the campaign, Zhu Xu, still loyal to his former state, revealed Qin deployments to the Jin and advised attacking before the Qin forces had fully assembled. Xie Xuan sent Liu Laozhi with five thousand elite troops across the Luo Stream, winning a major victory. Seeing the huge disparity in numbers, Xie Xuan then sent an envoy to the Qin camp asking its army to withdraw slightly so that the Jin troops could cross and fight on open ground. Fu Jian believed he could allow the Jin to begin crossing and then charge them with cavalry midstream, so he accepted. Once Qin troops began to withdraw, however, the movement became uncontrollable and their formation collapsed. Xie Xuan led more than eight thousand cavalry across the Fei River and attacked. Zhu Xu then shouted from the rear, “The Qin army is defeated! The Qin army is defeated!” Panic spread, and the enormous Qin force fled in collapse. Eastern Jin won the Battle of the Fei River.

Recovery of Imperial Authority and the Ruler–Chief Minister Standoff

The victory at the Battle of the Fei River preserved Eastern Jin, but it also changed the internal balance of power. In the ninth month of 383, the eighth year of Taiyuan, Emperor Xiaowu appointed his long-overlooked full younger brother Sima Daozi, Prince of Langya, Supervisor of the Six Divisions of the Secretariat, beginning to divide Xie An's power.

Although Xie An had directed the victory, he found himself in the awkward position of receiving little reward for towering achievements. Wang Guobao and others used slander and flattery to alienate the emperor from Xie An. Xie An, moreover, retained the sensibilities of an aristocratic gentleman and had little desire to struggle over power. He therefore yielded. In the eighth month of 384 he requested permission to lead a northern expedition; in the fourth month of the next year he moved out to Guangling and died in the eighth month. Sima Daozi then naturally became Inspector of Yangzhou and Commander-in-Chief of military affairs inside and outside the capital. With Xie An pushed aside and dead, Xie Xuan could no longer remain secure in command at Beifu. Following setbacks in the northern campaigns and illness, he relinquished military authority in the first month of 387 and retired as Administrator of Kuaiji, dying the next year. His retirement marked the end of the Chen Commandery Xie clan's dominance in aristocratic politics and, in the source's interpretation, the completion of Emperor Xiaowu's recovery of imperial authority.

Although Emperor Xiaowu now personally ruled and “authority issued from himself,” the source judges that he was not a capable ruler. Together with his younger brother Sima Daozi, he became absorbed in wine and women, making the court disorderly. He also embraced Buddhism and favored monks and nuns, while government grew increasingly dark. Beneath the outward appearance of the brothers' shared devotion to feasting and song, however, lay deep conflict, producing the late-Taiyuan situation known as the “standoff between ruler and chief minister.” The standoff was directly expressed through divisions within the Taiyuan Wang clan: the branch connected to Empress Wang, represented by Wang Gong, competed with the branch connected to the Princess of Langya, represented by Wang Chen.

Later Years and Assassination

In 396, the twenty-first year of Taiyuan, Sima Yao made a drunken joke to his favored consort Lady Zhang, saying that she was nearly thirty and, at her age, ought soon to be cast aside. Lady Zhang was furious. That night, while Sima Yao slept drunk in Qingshu Hall, she first used wine to send the eunuchs away to rest, then ordered serving women to cover the emperor's face with a quilt and smother him to death. Afterward she bribed the attendants heavily and announced that Sima Yao had “suddenly died from a nightmare.” In the eleventh month he was buried at Longping Mausoleum in the area of present-day Nanjing, Jiangsu.

Family, the Jianwen Emperor's Testament, and the Peril of His Accession

Sima Yao, styled Changming and the Xiaowu emperor of Jin, was born to the grand consort of Xiaowu, née Li Lingrong. His father Sima Yu had seven sons, of whom the first five died young, only Sima Yao and his brother (Sima Daozi) reaching manhood; when Sima Yu came to the throne and was enfeoffed as prince of Langya, the four-year-old Sima Yao succeeded him as prince of Kuaiji. In the eleventh month of 371 the great warlord Huan Wen brought troops into the capital and, by a palace coup, deposed Sima Yi as prince of Donghai through an order of the empress dowager Chongde and set up the prince of Langya, Sima Yu, as emperor — Jianwen — so that Sima Yao became an imperial son. Since Sima Rui founded the state in Jiangzuo, the Eastern Jin had lain under the alternate domination of the great clans (Wang, Yu, Huan and Xie), and "apart from (Yuandi and Mingdi), who did somewhat, the other emperors were little more than puppets"; under Jianwen this "weak throne and gentry monopoly" reached its extreme. It was said that "Huan Wen's power blazed then; the attendant Xie An bowed to him from afar, and Huan Wen asked in astonishment: 'Anshi, why such behaviour?' and An answered: 'There has never been a case of the lord bowing first and the minister merely saluting after'"; and the situation was summed up as "government from the Huan house, sacrifice from Us" — Huan Wen's ambition being to have Jianwen "abdicate in his favour."

Eight months after taking the throne Jianwen fell gravely ill. On the twenty-third day of the seventh month of 372 he sent four edicts in succession urging Huan Wen, still at (Gushu), to come to court as regent, and Huan Wen deliberately declined; five days later, his illness worsening, he made the prince of Kuaiji his (heir), and the testament he issued followed the precedent of (the Duke of Zhou's regency) and added that "if the young son can be assisted, assist him; if not, take it yourself." The state's fate hung by a thread, since Huan Wen might well have usurped on the strength of that testament. Wang Tanzhi, of the Taiyuan Wang, tore up the edict before Jianwen's own eyes, and Jianwen had to agree that it should be changed to "all matters of house and state to be reported to the grand marshal, as in the case of Lord Zhuge"; and when some at court still urged that "the grand marshal must decide," Wang Biaozhi said gravely: "The son of heaven has died and the crown prince succeeds — by what right should the grand marshal differ? To consult him first would only invite his reproach," and so the court settled it and the crown prince Sima Yao took the throne. The empress dowager Chongde then, on the ground of his youth and his mourning for his father, ordered Huan Wen again to act as regent after the Duke of Zhou, and Wang Biaozhi, holding that "this is no ordinary matter, and the grand marshal will surely decline, so that all business would halt and the tomb be delayed," would not receive the order. "At the very moment when the Jin house hung by a thread, the great clans joined to check Huan Wen's design of usurpation and secured Sima Yao's accession and the survival of the Eastern Jin."

The Passage of the Crisis, Xie An's Regency, and the Northern Garrison Army

Three months after his accession came the rising of the (Pengcheng magician) Lu Song, who with three hundred men forced his way into the (palace court), seized weapons from the arsenal and sought to restore the prince of Haixi (Sima Yi). Its "point was aimed at Huan Wen, and it objectively increased the effect of the Wang and Xie in resisting him"; Huan Wen came to the capital from Gushu in the second month of 373, "and rumour had it that he meant to kill the Wang and Xie and transfer the Jin throne, so that Wang Tanzhi and Xie An stood on their guard," though he only pursued the affair of Lu Song. He fell ill soon after and "even in illness demanded (the nine bestowals)" for himself, while Wang Tanzhi and Xie An delayed the matter; in the seventh month of that year he died, "and the crisis of the early years passed without disaster." Yet the structure of clan politics persisted: because of the emperor's youth, and to prevent Huan Wen's brother (Huan Chong) and other men of the Qiao Huan from continuing to monopolize power, Xie An brought out the emperor's elder brother's wife, the empress dowager Chongde, to (hold court), and the histories record that "the son of heaven being young and weak and strong ministers without, An and Tanzhi loyally supported and guarded him, and so the Jin house was preserved." In the fifth month of 375 Wang Tanzhi died and Xie An's power grew greater, he and (Huan Chong) holding the inner and outer positions "so as to form the balance of the Eastern Jin power structure"; in the eighth month of the same year the emperor married the daughter of (Wang Yun) of the Taiyuan Wang, while (the prince of Langya, Sima Daozi) married Wang Tanzhi's cousin's daughter — which kept the influence of the (Taiyuan Wang) at court "and laid the ground for the balance of ruler and minister of his later years."

Xie An's greatest weakness in power was that "he had no reliable military force to lean on": within he must guard against the Huan still (upstream), without against the growing Former Qin, and so in 377 he recommended his nephew Xie Xuan to hold Guangling, two years later adding the governorship of Xuzhou; Xie Xuan "recruited many strong men," and Liu Laozhi with He Qian of Donghai, Zhuge Kan of Langya, Gao Heng of Le'an, Liu Gui of Dongping, Tian Luo of Xihe and Sun Wuzhong of Jinling "were chosen for their fierceness," and Xie Xuan making Liu Laozhi his adviser "with picked troops as his vanguard, won a hundred battles out of a hundred, and they were called the Northern Garrison Army, which the enemy feared." The force "was of great fighting power, and not only strengthened the house of Xie but provided a firm guarantee for the survival of the Chinese regime in Jiangzuo."

The Qin Invasion, the Battle of the Fei River, and the Recovery of Imperial Power

In the fourth month of 378 Former Qin called out the men of Xu, Yan and Qing, and the Eastern Jin sent He Qian, interior secretary of Pengcheng, to patrol the Huai and Si in support, "so that from this time the Huan and Xie armies of the upper and lower rivers cooperated and answered one another, dividing the Qin spearhead — a feature of Eastern Jin strategy that did much to secure the final victory"; in the seventh month Qin too acted on east and west together, and by the first month of 379 Xiangyang fell, its defender (Zhu Xu) going over to Former Qin, "and Jiankang was in alarm, the position the worse for Eastern Jin." In the tenth month of 382 Fu Jian made his plan of a great attack public among the ministers, who "mostly opposed it," urging that (Xie An and Huan Chong) "are all great men of Jiangbiao, the ruler and ministers in harmony and of one mind within and without," but Fu Jian was set on it and went his own way, "having even arranged for the Xiaowu emperor to be made (president of the secretariat of the left)" — the record in Fu Jian's annals saying that he "wrote down the day of the expected victory, making the emperor president of the secretariat of the left, Xie An minister of personnel and Huan Chong attendant, and building houses ready for them." From the fifth to the seventh month of 383 Huan Chong counter-attacked Xiangyang with a hundred thousand men and detached officers northward, "a large-scale supporting action to relieve the pressure on Jiankang on the eve of the Fei river, which wore out Fu Jian's invading army"; and Xie Xuan's subordinate (Liu Laozhi) sent Hu Bin, interior secretary of Xuancheng, toward (Shouyang) "to support Huan Chong's army attacking Xiangyang, showing the unity of the two great clans, Huan and Xie, before the great enemy." Nor were they without friction: over the governorship of Jiangzhou "conflict arose again, and in the end the Xie yielded and the Xiaowu emperor let Huan Chong hold Jiangzhou himself," which "shows the latent contradictions among the clans, adding a discordant note beneath the appearance of common hatred of the enemy."

In the eighth month of 383 Fu Jian issued the edict for a great attack, "leading in person six hundred thousand infantry, two hundred and seventy thousand cavalry and thirty thousand guards, nine hundred thousand in all, marching south from Chang'an over several thousand li, by water and land at once, with ten thousand grain ships alone," boasting that "with my host, if we threw our whips into the river we should cut off its flow"; while the Eastern Jin had only eighty thousand men to meet them, with Xie Xuan's Northern Garrison Army as the main force. The Qin vanguard under (Fu Rong) reached Yingkou with three hundred thousand and "won the first engagement," taking (Shouyang) and cutting off the retreat of the relieving force under Hu Bin, which they surrounded at Xiashi; Fu Jian, delighted at the report, left the main army at (Xiangcheng) and rode to Shouyang with eight thousand light horse, and sent the captured Jin general Zhu Xu to call for surrender — but Zhu Xu "had his old country at heart, disclosed the whole Qin disposition and advised striking at once before the Qin were fully gathered," and the Jin army, which had meant to stand on the defensive, changed to attack. In the eleventh month Liu Laozhi led five thousand picked troops across the Luo river against fifty thousand of the enemy, "winning a great victory and beheading Liang Cheng and ten other Qin generals," and with confidence rising Xie Shi moved by water and land to camp by the (Fei) river facing the Qin at Shouyang. Xie Xuan sent an envoy asking the Qin to fall back a little and leave room for a decisive battle; Fu Jian, meaning to fall on the Jin as they crossed, ordered the retreat, "and at the first backward move the Qin lost control and their ranks fell into chaos"; Xie Xuan with more than eight thousand crossed the Fei and attacked fiercely, and Zhu Xu from behind the lines shouted that "the Qin army is beaten! the Qin army is beaten!" — the Qin troops, many conscripted and of many peoples, "of one bed and different dreams, their hearts unsteady at best," grew the more panicked and fled for their lives, "and the hundreds of thousands broke and ran like a falling mountain, throwing away armour and weapons."

Major Activities

Political Reform and Recovery of Imperial Authority

After assuming personal rule in 376, the first year of Taiyuan, Sima Yao reformed taxation. He abandoned taxation based on the amount of land held and instead levied three hu of rice per person from princes and nobles downward, with persons serving labor obligations exempted. During his reign he worked to strengthen imperial power and status. Historical accounts described him as having “authority issue from himself,” reversing the loss of imperial control that had followed the death of Emperor Ming of Jin. By placing his brother Sima Daozi in government in place of Xie An and pushing the Chen Commandery Xie clan aside, he recovered imperial authority and became, according to the source, the most powerful Eastern Jin emperor since the dynasty's establishment south of the Yangtze.

Battle of the Fei River

In 383, the eighth year of Taiyuan, Fu Jian, ruler of Former Qin, led what the source describes as an army of 900,000 south against Jin in an attempt to destroy the Eastern Jin state. Under chief minister Xie An, the Jin fielded about 80,000 troops, with Xie Shi as commander-in-chief, Xie Xuan commanding the vanguard, and Liu Laozhi as the principal field commander. At the Battle of the Fei River, Jin forces exploited the disorder caused by the Qin army's withdrawal and launched a sudden attack, winning a decisive victory. The source describes the battle as a famous example in Chinese history of a smaller force defeating a larger one and links it with the later expressions “casting whips to stop the river,” “startled by the wind and the cry of cranes,” and “seeing every tree and blade of grass as an enemy soldier.” The victory preserved the Eastern Jin state and created favorable conditions for later northern campaigns to recover lost territory.

Northern Expeditions and Territorial Expansion

After 384, the ninth year of Taiyuan, Emperor Xiaowu took advantage of Former Qin's collapse to launch northern expeditions. Eastern Jin successively recovered all territories south of the Yellow River, including Luoyang in Henan and the Shandong Peninsula, and Liu Laozhi even temporarily occupied Ye in Hebei. According to the source, Eastern Jin territory in the 390s reached its greatest extent since the dynasty's founding. Yet repeated warfare and sharply increased corvée and taxes caused great hardship and resentment among the population. Counterattacks by Zhai Wei, Later Qin, Later Yan, and other northern regimes, combined with infighting at the Eastern Jin court, resulted in the loss by the end of Emperor Xiaowu's reign of most of the territory north of the Huai recovered after the Fei River victory.

Patronage of Buddhism

Sima Yao was a believer in Buddhism. He favored monks and nuns, built numerous Buddhist temples in Jiankang, and supported the monastic community. The source associates the further development of Buddhism in the later Eastern Jin with his patronage, while also stating that favoritism toward monks and nuns worsened political disorder and became a target of ministerial criticism.

After the Fei River, and the Limits of Recovering Imperial Power

After the battle the Eastern Jin, seizing the moment of disorder in the north, recovered Ba-Shu and great tracts of Shandong and Henan, "advancing as far as (the Yellow River)"; yet "the counter-attacks of the Hu regimes and the internal strife at the Eastern Jin court caused the Huai-north lands recovered after the Fei river to be mostly lost again by the end of the Xiaowu reign." This rise and fall sums up the reign: his accession was the most dangerous handover in the whole of clan politics, and the state survived only because Wang Tanzhi, Xie An and Wang Biaozhi joined to check Huan Wen's usurpation; in mid-reign, with Xie An at the centre and Xie Xuan's Northern Garrison Army as its force, came the great victory at the Fei river and a temporary expansion; afterwards he turned to recovering imperial authority, forming with (his brother Sima Daozi) a balance of ruler and minister, from which new contradictions between the imperial house and the clans arose. Historians describe his early years by "the son of heaven young and weak, strong ministers without," and his last years by "a feeble imperial house" — which shows that throughout the Eastern Jin the throne's power ebbed and flowed under the constraint of two forces, the gentry and the imperial kin: Sima Yao could recover a part of the authority through circumstance and the choice of men, but could not change the structure itself; and his murder in the palace in his last years, after (a quarrel with a favourite consort), cut that brief recovery short.

Personal Relations

• Sima Rui: Grandfather; Emperor Yuan of Jin
• Sima Yu: Father; Emperor Jianwen of Jin
• Li Lingrong: Mother; Empress Dowager Xiaowuwen
• Sima Daozi: Full younger brother; Prince of Langya and Prince of Kuaiji
• Wang Fahui: Empress; granddaughter of Wang Meng of the Taiyuan Wang clan
• Lady Zhang: Favored consort; Chen Guinu: consort with the rank Shuyuan, later posthumously honored as Empress Dowager De
• Sima Dezong: Elder son; Emperor An of Jin
• Sima Dewen: Younger son; Emperor Gong of Jin
• Xie An: Principal decision-maker behind the Battle of the Fei River; later pushed aside
• Xie Xuan: Commander of the Beifu Army and vanguard leader at the Battle of the Fei River
• Wang Tanzhi: Member of the Taiyuan Wang clan who strongly opposed Huan Wen's attempt to usurp the throne
• Wang Biaozhi: Member of the Langya Wang clan who insisted on the Crown Prince's immediate accession
• Huan Wen: Powerful minister and greatest early threat to the reign
• Huan Chong: Huan Wen's younger brother and Inspector of Jingzhou
• Chu Suanzi: Empress Dowager Chongde, who presided over court
• Xie Shi: Commander-in-chief at the Battle of the Fei River
• Liu Laozhi: Famous Beifu Army general
• Zhu Xu: Former Eastern Jin commander who supplied intelligence to Jin during the Battle of the Fei River
• Wang Guobao: Partisan of Sima Daozi
• Wang Gong: Member of the Taiyuan Wang clan connected with Emperor Xiaowu's empress
• Wang Chen: Member of the Taiyuan Wang clan connected with the Princess of Langya's branch
• Huan Wen: Sought to usurp the Jin throne but was blocked by the aristocratic clans
• Fu Jian: Ruler of Former Qin, defeated by Eastern Jin at the Battle of the Fei River
• Lady Zhang: Killed the emperor after his drunken remark

Historical Assessment

Eastern Jin and Contemporary Assessments

• Xie An reportedly praised Sima Yao's ability in metaphysical discussion and subtle argument, considering his grasp of refined principles no less than that of his father, Emperor Jianwen.
• Historical accounts said that “authority issued from himself,” indicating contemporary recognition that he had reversed the loss of imperial power after the death of Emperor Ming of Jin.
• Wenren and Xu Rong submitted critical letters to the throne. Sima Yao knew them to be forthright but disliked hearing unwelcome words, reflecting the critical attitude of some contemporary officials.

Tang Period

• Fang Xuanling wrote in the Book of Jin: “Daozi neglected government at court; Guobao gathered petty men around him. Honors and appointments did not at first reflect the sovereign's will; money gained through the sale of punishments flowed of itself to the gates of power. Poisonous levies increased each year and the people's sorrow grew annually... He gave himself to drunkenness through the court day and sent cups flying through the long night.” The passage criticizes the indulgence and political darkness of the reign.
• Yu Shinan wrote: “Emperor Xiaowu overcame the external danger through Xie An's strength, not through the ruler's own achievement. By entrusting affairs to Kuaiji, the great beams were already bent; when Yin and Wang held the provincial commands, the steps toward disorder arose. The prophecy concerning Changming was fulfilled here. Moreover, in his later years he sank into banqueting and at last brought about collapse.” Yu attributed the Fei River victory to Xie An rather than Sima Yao and blamed the emperor's later indulgence for his downfall.

Song and Yuan Periods

• Sima Guang's Comprehensive Mirror in Aid of Governance records in detail how Sima Yao was killed by Lady Zhang and presents the outcome as a warning about the fatal consequences of his drunken remark.
• Song scholars often approved of Sima Yao's recovery of imperial authority and saw him as ending a phase of aristocratic political dominance, while also criticizing his later incompetence.

Modern Assessments

• Tian Yuqing, in Aristocratic Politics of the Eastern Jin, argued that Sima Yao exploited a temporary gap in aristocratic-clan leadership, sought to break the established system of aristocratic politics, and restore the Sima imperial house, becoming the most powerful emperor since Eastern Jin's foundation south of the Yangtze.
• Modern historians generally hold that victory at the Battle of the Fei River preserved Eastern Jin, but that Sima Yao's pursuit of pleasure, indulgence in wine and women, and struggle with Sima Daozi created the “ruler–chief minister standoff,” increasingly darkened politics, and culminated in an assassination that also reflected the broader decline of Eastern Jin imperial power.