智能愚笨

晋惠帝生于259年2月13日。晋惠帝于泰始三年（267年）被立为太子，他的母亲是晋武帝的皇后杨艳。作为次子的他被立为太子是因为其兄司马轨很早就死了，也有说是晋武帝为了将来传位给他宠爱的聪明孙子泯怀太子司马遹。

晋惠帝一般被评价为「甚愚」，王夫之说他是「土木偶人」，《晋书》中记载武帝担忧晋惠帝的能力，多次对他进行考验，而惠帝则在太子妃贾南风及谋臣的献策下通过了这些考验。即位后，他显然无法解决他统治时期的政治困难，造成了八王之乱，成为了傀儡，最后被东海王司马越毒死。

大事记

• 272年惠帝奉武帝命娶贾充之女贾南风为太子妃。

• 290年武帝去世，惠帝登基，尊继母杨芷（杨艳的堂妹）为皇太后，妻子贾南风为皇后，司马遹为太子。惠帝当政后非常信任他的皇后。因此贾氏专权，甚至假造惠帝的诏书。291年迫害皇太后，废其太后位，后又杀大臣如太宰司马亮。291年贾后杀太后。

• 294年和296年匈奴和其他少数民族反叛，氐人齐万年称帝，一直到299年这次反叛才被消灭。

• 同年贾后开始迫害太子遹，首先废他的太子地位。次年杀太子。这个举动成为许多反对贾后专政的皇族开始行动的起点。赵王司马伦假造诏书废杀贾后，杀大臣如司空张华等，自领相国位，这是八王之乱的开始。恢复原太子的地位，立故太子之子司马臧为皇太孙。300年八月淮南王司马允举兵讨伐司马伦，兵败被杀。同年十二月，益州刺史赵廞协同从中原逃到四川的流民在成都造反。

• 301年司马伦篡位，自立为皇帝，惠帝被改为太上皇，太孙司马臧被杀。三月，齐王司马冏起兵反司马伦，受到成都王司马颖、河间王司马顒、常山王司马乂等的支持。司马伦兵败。淮陵王司马漼杀司马伦的党羽，驱逐司马伦，引惠帝zh-hant:复; zh-hans:复;位。司马伦被杀。五月，立襄阳王司马尚为皇太孙，并以羊献容为皇后。六月，东莱王司马蕤谋推翻司马冏的专权，事漏被废。十二月，李特开始在四川反晋，这是成汉的起点。

• 302年初皇太孙司马尚夭折，司马覃被立为太子。五月，李特在四川击败了司马顒派去讨伐他的军队，杀广汉太守张微，自立为大将军。十二月，司马颖、司马顒、新野王司马歆和范阳王司马虓在洛阳聚会反司马冏的专政。司马乂乘机杀司马冏，成为朝内的权臣。

• 303年三月李特在攻成都时被杀，但四月他的儿子李雄就占领了成都，到年末，李雄几乎占领了整个四川盆地。五月张昌、丘沈反，建国汉，杀司马歆。八月，司马颖和司马顒讨伐司马乂。十月，司马顒的军队攻击首都洛阳，在此后的洗劫中上万人死亡。此后两军在洛阳城外对阵，连十三岁的少年都被征军，同时两军都徵募匈奴等的军队。最后司马乂兵败被杀。司马顒成为晋朝举足轻重的人物。

• 304年初惠帝感到受到司马顒的威胁越来越大，因此下密诏给刘沈和皇甫重攻司马顒，但没有成功。司马顒的军队在洛阳大肆抢劫。二月废皇后羊氏，废皇太子司马覃，立司马颖为皇太弟。司马颖和司马顒专政。但六月京城又发生政变，司马颖被逐，羊氏复位为皇后，司马覃复位为太子。七月，惠帝率军讨伐司马颖，在荡阴被司马颖的军队战败，惠帝面部中伤，身中三箭，被司马颖俘虏。羊氏和司马覃再次被废。八月，司马颖被安北将军王浚战败，他挟持惠帝逃亡到洛阳。一路上只有粗米为饭。十一月，惠帝又被司马顒的将军张方劫持到长安，张方的军队抢劫皇宫，将皇宫内的宝藏洗劫一空。到年末司马顒再次在长安一揽大权，司马越成为太傅。同年李雄在成都称成都王，成汉建国，刘渊自称汉王，建立前赵。305年司马顒和张方的军队、司马颖的军队、司马越的军队和范阳王司马虓的军队在中原混战，基本上中央政府已经不存在，晋朝边缘的地区纷纷独立。到305年末，司马越战胜，司马顒杀张方向司马越请和，但无效。

• 306年司马越手下的鲜卑军队攻入长安，大肆抢劫，二万多人被杀。九月，司马颖被俘，后被杀。永兴三年五月己亥（6月11日），晋惠帝跟随司马越的将军回到洛阳。六月丙辰（6月28日），晋惠帝又前往长安。

• 307年光熙元年十一月庚午（307年1月8日），惠帝于长安显阳殿因吃饼中毒去世，有传言说他是被司马越毒死。惠帝死后葬太阳陵。

家世

后妃

• 皇后贾南风

• 皇后羊献容

• 淑妃谢玖

子女

• 愍怀太子司马遹，母谢玖。

• 河东公主，母贾南风。嫁射声校尉孙会。

• 清河公主，后改封临海公主，母羊献容。嫁宗正曹统。

• 始平公主，母贾南风。

• 弘农郡公主司马宣华，母贾南风。

• 哀献皇女司马女彦，母贾南风。

特殊纪录

因为他在位期间全国先后经历八王之乱和五胡乱华等重大事件的影响，连带使他在中国历史上非自愿地创造纪录：

• 最多皇储（？，以上太弟、太孙加上太子，待另考）。

• #最多皇太弟（2个），司马颖、司马炽。

• #最多皇太孙（2个），司马臧、司马尚。

• 被自己的长辈尊为太上皇（司马伦为惠帝的叔公）。

• 其第二任皇后羊献容曾任2个不同政权君主的皇后，除晋惠帝外，后来又为前赵帝刘曜之后。

• 主政18年，用了9个年号。除了时间最长的元康年号（9年），9年间用了8个年号，更换年号的频率和武则天相当，使用过的年号数量则居武则天之后（武则天为帝的16年使用15个年号，为帝前握有实权的6年使用3个年号），中国众多皇帝的第二位。

由于晋惠帝的昏庸愚蠢名动天下，使居于上位原本不带贬意的諡号「惠」在他用过之后成了昏君代名词，故后来如唐宋这类长期统治中原的主流大朝代皆避免用惠字当皇帝諡号。

逸事

有人向晋惠帝报告老百姓无食物吃（天下荒饥，百姓饿死），他反问：「何不食肉糜？」（为何不吃肉粥？）。

有一次，晋惠帝游上林苑，听到蛤蟆叫，问身旁的人：「此鸣者，为官乎？为私乎？」（在叫的蛤蟆是官家的还是私人的啊？）

战乱时，嵇康之子嵇绍以身捍卫，血喷满惠帝整身，《晋书·忠义传·嵇绍》：「绍以天子蒙尘，承诏驰诣行在所。值王师败绩于荡阴，百官及侍卫莫不散溃，唯绍俨然端冕，以身捍卫，兵交御辇，飞箭雨集。绍遂被害于帝侧，血溅御服，天子深哀叹之。及事定，左右欲浣衣，帝曰：『此嵇侍中血，勿去。』（这是嵇侍中的血，不能去掉）」

注释

刘驰，《晋惠帝白痴辨──兼析其能继位的原因》，原载《中国历史大辞典通讯》第4期（1984）https://web.archive.org/web/20050318154528/http://6ch.com.cn/data/articles/c02/88.html

外部链接

Life prior to ascension

Sima Zhong was born to Sima Yan and his wife Yang Yan in 259 AD, while Sima Yan was still the assistant to his father, the Cao Wei regent Sima Zhao. He was their second son, but after the early death of his older brother Sima Gui (司马轨), he became the oldest surviving son. It is not known when his developmental disabilities became apparent, but, in any case, after Sima Zhao died in September 265, and Sima Yan subsequently forced the Cao Wei emperor Cao Huan to abdicate to him in February 266 (which ended Cao Wei's reign and started Jin's as Emperor Wu), he made the seven-year-old Prince Zhong crown prince in 267 AD.

As Crown Prince Zhong grew in age, his developmental disabilities became clear to his parents and the imperial officials alike. He learned how to write and speak, but appeared to be unable to make logical decisions on his own at all. Once, when he heard frogs croaking, he asked, in all seriousness, "Do they croak because they want to, or because the government ordered them to?" Several times, officials reminded Emperor Wu of this, but Emperor Wu, not realizing the extent of Crown Prince Zhong's disability, resisted the implicit calls for him to be replaced. Indeed, because Emperor Wu was concerned that many officials were impressed with his talented younger brother, Sima You the Prince of Qi and might want Prince You to replace him instead, he eventually had Prince You sent to his principality, and Prince You died in anger in 283.

In 272, at age 12, Crown Prince Zhong married Jia Chong's daughter Jia Nanfeng, who at 14 was two years older. Crown Princess Jia was violent and jealous, but had her methods of controlling Crown Prince Zhong so that he both loved and feared her. She bore him four daughters during their marriage, but she would not bear his only son Sima Yu – whose mother Consort Xie Jiu was originally a concubine of Emperor Wu, but had been given to Crown Prince Zhong prior to his marriage to Crown Princess Jia, so that Consort Xie could teach him how to have sexual relations. Consort Xie became pregnant and bore Sima Yu, who was much favored by his grandfather Emperor Wu. Emperor Wu considered Prince Yu intelligent and very much like his own grandfather Sima Yi, and this played into his decision not to replace Crown Prince Zhong. However, other than Consort Xie, no other concubine would bear Crown Prince Zhong a child—as several had been pregnant but each was murdered by Crown Princess Jia, in fits of jealousy. (Emperor Wu, in anger, considered deposing Crown Princess Jia, but with the intercession of his second wife Empress Yang Zhi, he recalled Jia Chong's contributions to the establishment of Jin Dynasty, and decided to leave her in place.)

In 289, as Emperor Wu neared death, he considered whom to make the regent for Crown Prince Zhong. He considered both Empress Yang's father Yang Jun and his uncle Sima Liang the Prince of Ru'nan, the most respected of the imperial princes. As a result, Yang Jun became fearful of Sima Liang and had him posted to the key city of Xuchang (许昌, in modern Xuchang, Henan). By 290, Emperor Wu resolved to let Yang and Sima Liang both be regents, but after he wrote his will, the will was seized by Yang Jun, who instead had another will promulgated in which Yang alone was named regent. Emperor Wu died soon thereafter, and Crown Prince Zhong ascended the throne as Emperor Hui. Crown Princess Jia became empress, and Prince Yu became crown prince.

Reign

During his 17-year reign, Emperor Hui would come under the control of a number of regents, never being able to assert authority on his own. The rough succession order of the regents were:

• Yang Jun: 290–291

• Sima Liang/Wei Guan: 291

• Empress Jia Nanfeng: 291–300

• Sima Lun: 300–301

• Sima Jiong: 301–302

• Sima Ai: 302–304

• Sima Ying: 304

• Sima Yong: 304–306

• Sima Yue: 306–307

Regency of Yang Jun

Yang Jun quickly showed himself to be autocratic and incompetent, drawing the ire of many other nobles and officials. He tried to appease them by making many bestowments of titles and honors among them, but this only brought further contempt for his actions. He knew Emperor Hui's empress Jia Nanfeng to be strong-willed and treacherous, so he tried to put people loyal to him in charge of all the defense forces of the capital Luoyang, and also ordered that all edicts not only be signed by the emperor but also by Empress Dowager Yang before they could be promulgated.

Empress Jia, however, wanted to be involved in the government, and was angry that she was constantly rebuffed by Empress Dowager Yang and Yang Jun. She therefore conspired with the eunuch Dong Meng (董猛) and the generals Meng Guan (孟观) and Li Zhao (李肇) against the Yangs. She tried to include Sima Liang into the conspiracy, but Sima Liang declined; instead, she persuaded Emperor Hui's brother, Sima Wei the Prince of Chu, to join her plan. In 291, after Sima Wei returned to Luoyang from his defense post (Jing Province (荆州, modern Hubei and Hunan)) with his troops, a coup went into progress.

Empress Jia, who had her husband easily under her control, had him issue an edict declaring that Yang Jun had committed crimes and should be removed from his posts. It also ordered Sima Wei and Sima Yao (司马繇) the Duke of Dong'an to attack Yang's forces and defend against counterattacks. Quickly, it became clear that Yang was in trouble. Empress Dowager Yang, trapped in the palace herself, wrote an edict ordering assistance for Yang Jun and put it on arrows, shooting it out of the palace. Empress Jia then made the bold declaration that Empress Dowager Yang was committing treason. Yang Jun was quickly defeated, and his clan was massacred. Empress Dowager Yang was deposed and imprisoned (and would die in 292 in imprisonment). Sima Liang was recalled to serve as regent, along with the senior official Wei Guan.

Regency of Sima Liang and Wei Guan

To appease those who might have been angry and had overthrown Yang Jun, Sima Liang also widely promoted those who participated in the plot, and more than a thousand men were created marquesses. He and Wei, however, did try to get the government on track, but Empress Jia continued to interfere with governmental matters. They also became concerned about the violent temper of Sima Wei and therefore tried to strip him of his military command, but Sima Wei persuaded Empress Jia to let him keep his military command. Sima Wei's assistants Qi Sheng (岐盛) and Gongsun Hong (公孙宏) thereafter falsely told Empress Jia that Sima Liang and Wei planned to depose the emperor. Empress Jia, who had already resented Wei for having suggested that the heir selection be changed during Emperor Wu's reign, desired more direct control over the government, and therefore resolved to initiate a second coup d'état.

In summer 291, Empress Jia had Emperor Hui personally write an edict to Sima Wei, ordering him to have Sima Liang and Wei removed from their offices. His forces thereby surrounded Sima Liang and Wei's mansions, and while both men's subordinates recommended resistance, they each declined and were easily captured. Contrary to the edict's terms, both were killed—Sima Liang with his heir Sima Ju (司马矩) and Wei with nine of his sons and grandsons. Qi then suggested to Sima Wei to take the opportunity to massacre Empress Jia's relatives and take over the government himself, but Sima Wei hesitated— at the same time, Empress Jia came to the realization that if the murders of Sima Liang and Wei could be traced to her instigation, that would bring a political firestorm' also that Sima Wei could not be easily controlled. She therefore publicly declared that Sima Wei had falsely issued the edict. Sima Wei's troops abandoned him, and he was captured and executed. Sima Liang and Wei were posthumously honored. From this point on, Empress Jia became the undisputed power behind the throne for several years.

Regency of Empress Jia

Empress Jia was now in control in close association with several advisors that she trusted—the capable official Zhang Hua, her cousins Pei Wei and Jia Mo (贾模), and her nephew Jia Mi (originally named Han Mi but posthumously adopted into the line of Jia Chong's son Jia Limin (贾黎民)). She also closely associated with her distant cousin-once-removed Guo Zhang (郭彰), her sister Jia Wu (贾午), and Emperor Wu's concubine Zhao Chan (赵粲). She lacked self-control, and was violent and capricious in her ways, but Zhang, Pei, and Jia Mo were honest men who generally kept the government in order. However, as she grew increasingly unbridled in her behavior (including committing adultery with many men and later murdering them to silence them), Zhang, Pei, and Jia Mo considered deposing her and replacing her with Crown Prince Yu's mother Consort Xie, but they hesitated and never took actual action. After Jia Mo died in 299, it became even harder to control her actions.

In 296, the Di and Qiang of Qin (秦州, modern eastern Gansu) and Yong (雍州, modern central and northern Shaanxi) started a major rebellion against Jin Dynasty, and they supported the Di chieftain Qi Wannian to be emperor. In 297, the Jin general Zhou Chu (周处), without support from the central government, was easily defeated by Qi. A large group of refugees, most of Di ancestry, stricken by the famine that resulted from the warfare, fled south into Yi Province (modern Sichuan and Chongqing), led by Li Te. (Several years later, they would eventually be forced into rebellion and peel away from Jin rule.) In 299, Meng Guan was able to defeat Qi, but Qi foreshadowed much more serious non-Han rebellions of the future. Later in 299, the mid-level official Jiang Tong (江统) would petition Empress Jia to have the five non-Han ethnicities (the Wu Hu) removed from the empire proper and relocated to regions outside the empire, but Empress Jia did not accept his suggestions.

The relationship between Empress Jia and Crown Prince Yu had always been an uneasy one. Empress Jia's mother Guo Huai had constantly advised Empress Jia to treat Crown Prince Yu well, as her own son, and she advocated marrying Jia Mi's sister to Crown Prince Yu. However, Empress Jia and Jia Wu opposed this, and instead married a daughter of the official Wang Yan to Crown Prince Yu. (Wang had two daughters, but Empress Jia had Crown Prince Yu marry the less beautiful one and had Jia Mi marry the more beautiful one.) After Lady Guo's death, the relationship between Empress Jia and Crown Prince Yu quickly deteriorated, as Jia Wu and Consort Zhao provoked difficulties between them. Further, Crown Prince Yu and Jia Mi never liked each other, and Jia Mi, as a result, also advised Empress Jia to depose Crown Prince Yu. In 299, Empress Jia agreed and took action. When Crown Prince Yu was in the palace to make an official petition to have his ill son Sima Bin (司马彬) created a prince, Empress Jia forced him to drink a large amount of wine and, once he was drunk, had him write out a statement in which he declared intention to murder the emperor and the empress and to take over as emperor. Empress Jia presented the writing to the officials and initially wanted Crown Prince Yu executed—but after some resistance, she only had him deposed and reduced to the status of a commoner. Crown Prince Yu's mother Consort Xie was executed, as was his favorite concubine Consort Jiang Jun (蒋俊).

In 300, under the advice of a prince she favored—Sima Lun the Prince of Zhao, Emperor Wu's granduncle—Empress Jia decided to eliminate Crown Prince Yu as a threat. She sent assassins and had Crown Prince Yu assassinated. Sima Lun, however, had other plans—he wanted to have Empress Jia murder the crown prince so that he could use the murder as an excuse to overthrow her, and he started a coup later that year, killing Jia Mi, Zhang, Pei, and other associates of Empress Jia. Empress Jia was deposed and later forced to commit suicide. Sima Lun and his strategist Sun Xiu became the paramount authority.

Regency of and usurpation by Sima Lun

Sima Lun restored the late Crown Prince Yu's reputation and had his son, Sima Zang (司马臧), created crown prince. However, Sima Lun himself had designs on the throne, and he and Sun Xiu became partial to placing those who favored them in power. Emperor Hui's brother, Sima Yun (司马允) the Prince of Huai'nan, correctly determined what Sima Lun's ambitions were, and as a result, Sima Lun and Sun tried to strip Sima Yun's military command. When Sima Yun read the edict ordering him to turn over the troops, he saw that it was Sun Xiu's handwriting—and became enraged and started a rebellion with his troops. Initially, he had successes against Sima Lun's troops and was almost able to capture Sima Lun's mansion, during the course of one day. Late in the day, Chen Zhun (陈准), who secretly supported Sima Yun, persuaded Emperor Hui to give him a banner that showed imperial support and was able to deliver it to Sima Yun, but his messenger, a friend of Sima Lun's son Sima Qian (司马虔), instead tricked Sima Yun into receiving the banner and, as he did, cut off his head. His troops disbanded after his death.

After defeating Sima Yun, Sima Lun became ever more intent on usurping the throne. Late in 300, after Sun Xiu's suggestion, Sima Lun was granted the nine bestowments. However, Sima Lun and his sons were themselves foolish and unintelligent, and Sun was the actual person in charge of the government. In the winter, Sun had the granddaughter of his distant relative and friend Sun Qi (孙旗), Yang Xianrong, married to Emperor Hui to be his empress.

Also in winter 300, the governor of Yi Province, Zhao Xin (赵廞), a relative of Empress Jia, rebelled and tried to occupy Yi Province to be his own domain. He associated with Li Te and his brother Li Xiang (李庠), and they soon were able to take over Yi Province. However, he then became suspicious of the Li brothers' abilities, and he killed Li Xiang after Li Xiang suggested that he declare himself emperor. Li Te, in anger, took his troops and killed Zhao. Li then welcomed the new Jin governor Luo Shang to the provincial capital Chengdu (成都, in modern Chengdu, Sichuan), but maintained an uneasy relationship with Luo and Luo's main strategist, Xin Ran (辛冉), a former friend of his who deeply suspected his intentions.

In spring 301, Sima Lun had Emperor Hui yield the throne to him, and gave Emperor Hui the honorific title of retired emperor (太上皇). In order to appease those who might be angry at his usurpation, he rewarded many people with honors. Sun, in particular, was issuing edicts based on his own whims. Suspecting three key princes – Sima Jiong the Prince of Qi (Emperor Hui's cousin and the son of Emperor Hui's uncle, Prince You of Qi), Sima Ying the Prince of Chengdu (Emperor Hui's brother), and Sima Yong the Prince of Hejian (the grandson of Emperor Hui's great-granduncle Sima Fu the Prince of Anping), each of whom had strong independent military commands—Sun sent his trusted subordinates to be their assistants. Prince Jiong refused and declared a rebellion to restore Emperor Hui. Prince Ying, Sima Ai the Prince of Changsha (Emperor Hui's brother), and Sima Xin (司马歆) the Duke of Xinye (the son of a granduncle of Emperor Hui) all declared support for Prince Jiong. Prince Yong initially sent his general Zhang Fang with intent to support Sima Lun, but then heard that Princes Jiong and Ying had great forces, and so declared for the rebels instead. Sima Lun's forces were easily defeated by Princes Jiong and Ying's forces, and after just declaring himself emperor for three months, Sima Lun was captured by officials in Luoyang who declared for the rebellion as well, and forced to issue an edict returning the throne to Emperor Hui. He was then forced to commit suicide. Sun and other associates of Sima Lun were executed.

Some thought that a power balance that Emperor Wu had hoped for at his death might be restored, as Princes Jiong and Ying were each given regent titles (and awarded the nine bestowments, in one rare case where the nine bestowments were not signs of an impending usurpation, although Prince Ying declined the bestowments), and many talented officials were promoted into important positions. However, the Princes Jiong and Ying were actually apprehensive of each other's power, and Prince Ying decided to yield the central government regency to Prince Jiong at the time and return to his defense post at Yecheng.

Regency of Sima Jiong

Meanwhile, Luo Shang ordered that the Qin/Yong refugees to go home and that they surrender all property that they pillaged during the wars of Zhao's rebellion. This caused great burden and fear on the refugees, and Li Te requested a one-year extension; Luo agreed, but Xin Ran and other officials under Luo were unhappy and secretly planned an attack on Li. Li, anticipating that this might happen, was prepared, and he defeated Xin's forces easily.

In the capital, Sima Jiong became arrogant based on his accomplishments. He had his sons created princes, and ran the matters of the central government from his mansion, rarely visiting the emperor or attending the imperial meetings. He enlarged his mansion to be as large as the palace, and he entrusted matters to people who were close to him, and would not change his ways even when some of his more honest associates tried to change his behavior. When Emperor Hui's grandsons Sima Zang and Sima Shang (司马尚), successive crown princes, died in childhood, leaving Emperor Hui without male descendants by 302, Sima Ying was considered the appropriate successor, but Sima Jiong chose to bypass him by recommending the seven-year-old Sima Qin (司马覃) the Prince of Qinghe (Emperor Hui's nephew and the son of his brother Sima Xia (司马遐)) as the crown prince, with intent to easily control the young Crown Prince Qin.

Sima Jiong became suspicious of Sima Yong the Prince of Hejian—because Sima Yong had initially wanted to support Sima Lun, until he saw that Sima Lun's cause was hopeless. Sima Yong knew of Sima Jiong's suspicion, and started a conspiracy; he invited Sima Ai the Prince of Changsha to overthrow Sima Jiong, believing that Sima Ai would fail; his plan was then to, in conjunction with Sima Ying, start a war against Sima Jiong. Once they were victorious, he would depose Emperor Hui and make Sima Ying the emperor, and then serve as Sima Ying's prime minister. In winter 302, Sima Yong declared his rebellion, and Sima Ying soon joined, despite opposition from his strategist Lu Zhi (卢志). Hearing that Sima Ai was part of the conspiracy as well, Sima Jiong made a preemptive strike against Sima Ai, but Sima Ai was prepared and entered the palace to control Emperor Hui. After a street battle, Sima Jiong's forces collapsed, and he was executed. Sima Ai became the effective regent, but in order to reduce opposition, he submitted all important matters to Sima Ying, still stationed at Yecheng.

Regency of Sima Ai

Sima Ai, of the princes, appeared to be the only one who saw the importance of formally honoring Emperor Hui while maintaining resemblance to impartial governance. He continued to try to share power with Sima Ying.

Meanwhile, in Yi Province, in 303, Luo Shang, after causing Li Te to be ready by offering a truce, made a surprise attack against Li's forces and killed him. Li's forces fell under the command of his brother Li Liu, who died later that year as well and was succeeded by his nephew Li Xiong. Under Li Xiong's command, the refugee forces were able to defeat not only Luo's forces but also reinforcements sent by Jing Province (荆州, modern Hubei and Hunan). At the same time of Li's successes, many agrarian rebellions also started throughout the empire, including one that defeated the forces of the powerful Sima Xin the Prince of Xinye and killed him.

In fall 303, Sima Yong, dissatisfied that his plan did not come to fruition, persuaded Sima Ying to again join him against Sima Ai. While Sima Yong and Sima Ying had overwhelming force, their forces could not score a conclusive victory against Sima Ai. Sima Yong's forces were about to withdraw in spring 304 when Sima Yue the Prince of Donghai, the grandson of a great-granduncle of Emperor Hui, believing that Sima Ai could not win this war, arrested him and delivered him to Sima Yong's general Zhang Fang, who executed Sima Ai cruelly by burning him to death. Sima Ying became in effective control of the government, but continued to control it remotely from Yecheng.

Regency of Sima Ying

Once Sima Ying became in effective control of the government, he deposed Crown Prince Qin and made himself crown prince instead, and he also deposed Empress Yang—the first of four times she would be deposed during a duration of two years. He became arrogant and extravagant, and the people became disappointed. Seeing this, Sima Yue decided to resist; he welcomed Empress Yang and Crown Prince Qin back to their positions, and, in Emperor Hui's name, set out to attack Sima Ying. His forces were defeated by Sima Ying's, and he fled, leaving Emperor Hui in Sima Ying's hands at Yecheng. Sima Yong's forces entered Luoyang and deposed Empress Yang and Crown Prince Qin again.

Wang Jun, the military commander of You Province (幽州, modern Beijing, Tianjin, and northern Hebei), who had an uneasy relationship with Sima Ying up to this point, then declared war against Sima Ying and headed south with his troops, allied with various Xianbei and Wuhuan tribes. Sima Ying found it difficult to resist them, and he sent one of his subordinates, the Xiongnu noble Liu Yuan, to his own tribesmen to ask them to join him. Once Liu left, however, Sima Ying's forces collapsed. When Liu heard this, instead of bringing his forces to Sima Ying's aid, he declared independence and entitled himself the Prince of Han—claiming rightful inheritance of Han Dynasty, as he claimed to be descended from a Han princess who had married a Xiongnu chanyu – and thus establishing Han Zhao. (A month earlier, Li Xiong had declared himself independent of Jin as well, as the Prince of Chengdu, establishing Cheng Han; these two states would be the first two of the Sixteen Kingdoms.)

Sima Ying fled back to Luoyang with Emperor Hui, but now with no forces backing him. Sima Yong, in control of the situation, decided to directly take control without using Sima Ying any longer, and Sima Ying was removed from the crown prince position and replaced with another brother of Emperor Hui's – Sima Chi the Prince of Yuzhang, who was considered studious and humble. Sima Yong also had Zhang Fang forcibly move Emperor Hui to Chang'an (in modern Xi'an, Shaanxi), directly under his own grasp. However, a number of high-level officials remained in Luoyang and formed a separate government that was partially allied with and partially rivalling Sima Yong's.

Regency of Sima Yong

Sima Yong tried to appease possible opposing forces by promoting all of the major princes and warlords, but his promotions did not have the desired effect. Meanwhile, Han Zhao attracted those Han and non-Han agrarians and tribesmen disappointed in Jin rule, and began to grow in size and power.

At the same time, however, the Jin infighting continued. In the fall of 305, Sima Yue declared yet another rebellion, this time against Sima Yong, claiming that Sima Yong had improperly forced Emperor Hui to move the capital. Various provincial governors and military commanders were forced to be on one side or the other. The war was initially inconclusive. In early 306, after a few victories by Sima Yue, Sima Yong became fearful, and he executed Zhang to seek peace; Sima Yue refused. By summer 306, Sima Yong was forced to abandon both Chang'an and Emperor Hui, and Sima Yue's forces welcomed Emperor Hui back to Luoyang and restored Empress Yang.

Also in 306, both Li Xiong and Liu Yuan declared themselves emperors, even more clearly breaking from Jin.

Regency of Sima Yue and death

Sima Yue served as regent for Emperor Hui for several months until winter 306 when, for an unknown reason, Emperor Hui was poisoned while eating bread. (Historians commonly accept Sima Yue as the culprit, but the motive is not clear.) Thus ended the reign of an emperor who suffered much and under whose reign the Jin dynastic system came crashing down, even though he himself should probably not be blamed for it. Crown Prince Chi succeeded him (as Emperor Huai) and would try to restrengthen the empire, but it was too late for Jin by that point. It would end up losing northern and central China to Han Zhao and be forced to relocate to southern China, continued in a branch line of the imperial clan.

Heirs

• 290–300: Sima Yu, Crown Prince Minhuai 泯怀太子司马遹 (son of Emperor Hui)

• 300–301: Sima Zang, Crown Prince Minchong 泯冲太孙司马臧 (son of Crown Prince Minhuai)

• 301–302: Sima Shang, Crown Prince Huaichong 怀冲太孙司马尚 (son of Crown Prince Minhuai)

• 302–304: Sima Tan 司马覃 (nephew of Emperor Hui)

• 304–304: Sima Ying, Prince of Chengdu 成都王司马颖 (brother of Emperor Hui)

• 304–304: Sima Chi, Prince of Yuzhang 豫章王司马炽 (brother of Emperor Hui)

Era names

• Yongxi (永熙 yǒng xī) May 17, 290 – February 15, 291

• Yongping (永平 yǒng píng) February 16 – April 23, 291

• Yuankang (元康 yuán kāng) April 24, 291 – February 6, 300

• Yongkang (永康 yǒng kāng) February 7, 300 – February 3, 301

• Yongning (永宁 yǒng níng) June 1, 301 – January 4, 303

• Taian (太安 tài ān) January 5, 303 – February 21, 304

• Yongan (永安 yǒng ān) February 22 – August 15, 304; December 14, 304 – February 11, 305

• Jianwu (建武 jiàn wǔ) August 16 – December 13, 304

• Yongxing (永兴 yǒng xīng) February 12, 305 – July 12, 306

• Guangxi (光熙 guāng xī) July 13, 306 – February 19, 307

Family

Consorts and Issue:

• Empress, of the Jia clan (皇后 贾氏; 257–300)

　• Princess Hedong (河东公主), personal name Xuanhua (宣华)

　　• Married Sun Hui (孙会; d. 301) in 300

　　• Married Fu Xuan (傅宣)

　• Princess Shiping (始平公主), personal name Nüyan (女彦)

• Empress, of the Yang clan of Taishan (皇后 泰山羊氏; d. 322), personal name Xianrong (献容)

　• Princess Linhai (临海公主)

　　• Married Cao Tong (曹统)

• Shuyuan, of the Xie clan (淑媛 谢氏; d. 300), personal name Jiu (玖)

　• Sima Yu, Crown Prince Minhuai (愍怀皇太子 司马遹; 278–300), first son

Ancestry