Early life and career

Huan Wen was born in 313 in . His father Huan Yi (桓彝) was a commandery governor. When he was young, his father once received a visit from Wen Jiao, who saw the boy and thought that the child was special. Huan Yi, because Wen had a high opinion of the child, thus named his son Wen, after Wen Jiao's family name.

In 328, during the rebellion of Su Jun, Huan Yi tried to resist Su's forces, but was defeated and killed by Su's general Han Huang, who received help from Huan Yi's subordinate Jiang Bo (江播). In 330, after Jiang had already died, Huan Wen killed Jiang's sons to avenge his father, and this was an act that brought him great fame. As he was considered capable, and his father had died for the imperial cause, he was selected as the husband for Emperor Cheng's sister Sima Xingnan (司馬興男) the Princess Nankang. He inherited his father's title of the Baron of Wanning, and he gradually rose in rank, eventually becoming the governor of Xu Province (徐州, then modern central Jiangsu). Emperor Cheng's uncle Yu Yi (庾翼) was impressed with his talent, and often endorsed him for even greater responsibilities. During Emperor Kang's brief reign, Huan was one of the few officials who supported Yu's plan for a northern campaign against Later Zhao in 343, although Yu's plan was never actually carried out. After Yu's death in 345 (during the reign of Emperor Mu, then a toddler), the chancellor He Chong (何充) commissioned Huan to succeed Yu, as the commander of the military forces in the western provinces (roughly modern Hubei, Hunan, Guizhou, and Yunnan), even though some other imperial officials had misgivings about Huan's ambitions and independence.

Campaign against Cheng Han

Soon after taking over for Yu, the ambitious Huan turned his attention west, wanting to destroy Cheng Han, whose emperor Li Shi had mismanaged his state and lost the trust of his people. Most generals had concerns about the geographic barriers that isolated Cheng Han (which occupied modern Sichuan and Chongqing) from Jin, and that Later Zhao might make a surprise attack if it realized that Jin's forces were attacking Cheng Han. Late in 346, he launched the campaign. Li Shi sent his uncle Li Fu (李福), cousin Li Quan (李權), and Zan Jian (昝堅) to lead his forces to resist Huan, but Huan defeated Li Fu and then, abandoning most of his supplies and traveling light, quickly arrived in the vicinity of Cheng Han's capital Chengdu. Zan Jian's forces, in fear, collapsed, instead of being able to regroup to try to save Chengdu.

However, Li Shi gathered the remaining troops and mounted a counterattack that was initially successful. Huan, in fear, ordered retreat—but his signal officer, in panic, beat his drums (signifying attack) rather than his gong (signifying retreat). The Jin forces attacked harder and defeated Cheng Han forces, allowing Huan to march upon Chengdu's gates. Li Shi fled, but soon had a messenger submit a humble surrender petition to Huan. He then surrendered in person after binding himself and bringing a coffin—signifying readiness to be executed. Huan released him and escorted him to the Jin capital Jiankang, where Emperor Mu pardoned him and created him a marquess. To reward Huan, Emperor Mu created him the Duke of Linhe.

Mutual suspicion with imperial officials

The victory over Cheng Han, however, brought fear in imperial officials that the ambitious Huan intended to control the government. Emperor Mu's granduncle Sima Yu, Prince of Kuaiji, in order to counter Huan, invited a renowned official, Yin Hao, to join in major decision-making with him and Cai Mo. This brought a rivalry that Huan and Yin had since their youth (when both were viewed as up-and-coming talent) into the open. The rivalry intensified after Yin seized more power late in 350 after accusing Cai of being disrespectful to the emperor (by repeatedly declining an honor that was being bestowed on him) and demoting Cai to commoner status.

Over the next few years, as Later Zhao collapsed in the midst of internecine wars between the emperor Shi Hu's sons and adoptive grandson Shi Min after Shi Hu's death in 349, Huan repeatedly requested the imperial government to authorize him to advance north to try to recover northern China for Jin, but he was repeatedly rebuffed, even after a campaign by Emperor Mu's maternal grandfather Chu Pou (褚裒) ended badly. Around the new year 352, Huan, upset that his requests were being repeatedly denied, mobilized his troops and gestured as if he were about to attack the capital. Yin was shocked, and initially considered either resigning or send the imperial banner of peace (Zouyu Fan, 騶虞幡) to order Huan to stop. After advice from Wang Biaozhi (王彪之), however, he instead asked Sima Yu to write a carefully worded letter to Huan, persuading Huan to stop.

Yin, meanwhile, was preparing his own campaigns, and he launched one campaign in the middle of 352 and one late in 352—the second one being thoroughly disastrous, as he offended and intimidated the general Yao Xiang (姚襄) into rebellion, and was ambushed by Yao at great loss of life and materials. The people despised Yin for his military losses, and Huan submitted a petition demanding Yin's ouster. The imperial government was compelled to demote Yin to commoner status and exile him. From that point on, the imperial government largely no longer dared to deny Huan's requests.

Northern campaigns

Against Former Qin

With Yin out of the picture, Huan launched a major attack against one of Later Zhao's successor states, Former Qin, in 354. His army defeated much of Former Qin's resistance, reaching all the way to the vicinity of Former Qin's capital Chang'an—but Huan hesitated at making one final assault against Chang'an. It was at this time that Huan met Wang Meng, who came to see him. Huan was impressed at Wang's knowledge and tactics, and he asked Wang why the people of the Qin lands were not shifting their allegiance to Jin, and Wang pointed out that the people were not sure what Huan's intentions were, given that he hesitated at crossing the Ba River (灞水), just east of Chang'an. As the situation stalemated, Huan began to run out of food supplies was forced to withdraw. He invited Wang to withdraw with him, but Wang declined, apparently believing that Huan was not the right person to follow. (Wang would eventually become the prime minister of the Former Qin emperor Fu Jiān a decade later.)

Against Yao Xiang

In 356, Huan submitted a petition requesting that the capital be moved back to Luoyang—the capital until its fall in 311 to Han Zhao - but the imperial government declined, instead ordering him to first attack Yao Xiang, who had taken many cities in the Luoyang region after rebelling against Yin Hao earlier. Huan advanced his troops to Luoyang and faced Yao in battle, and he eluded a trap Yao laid for him and dealt Yao a major defeat, forcing Yao to head west. (Yao would eventually be captured and killed by Former Qin in 357.) Huan secured the Luoyang region for Jin. He, in 362, reproposed the idea of moving the capital back to Luoyang, but the imperial government again declined.

Against Former Yan

For the next few years, Huan largely spent his effort in securing his power, as he invited many capable people to join his staff, including Xie An, Wang Tanzhi, Chi Chao, Wang Xun, and Xie Xuan. He did not carry out another northern campaign, apparently not willing to face the capable Former Yan general Murong Ke in battle. (Indeed, when Murong Ke's brother, the Former Yan emperor Murong Jun died in 360 and was succeeded by his young son Murong Wei, contrary to the optimism that many Jin officials had that with Murong Jun out of the way that Former Yan would be weakened, Huan commented, "Murong Ke is still alive, and I am afraid that we have an even greater problem.") In 364, Emperor Ai, who succeeded Emperor Mu in 361, suffered a poisoning after taking pills given to him by magicians in search of immortality, and Huan was initially summoned to the capital to serve as regent, but a second order was then issued him cancelling that summon. Instead, he set up his base at Zheqi (赭圻, in modern Wuhu, Anhui) and monitored the situation at Jiankang remotely.

In 365, Murong Ke attacked Luoyang, and initially, Huan and Sima Yu were planning a counterattack to relieve Luoyang, but the plan was cancelled after Emperor Ai died in spring 365. Soon, Luoyang fell.

Late in 365, the Jin general Sima Xun, the governor of Liang Province (梁州, modern southern Shaanxi), who had participated in many campaigns, rebelled, and Huan commissioned one of his generals, Zhu Xu, to attack Sima. Sima was soon captured and killed.

After Murong Ke died in 367, Huan began to plan to attack Former Yan, whose regime was now largely in the hands of Murong Wei's granduncle Murong Ping the Prince of Shangyong, regarded as incompetent and corrupt, and Murong Wei's mother Empress Dowager Kezuhun. In 369, he launched the campaign, in conjunction with Chi Chao's father Chi Yin (郗愔), his brother Huan Chong, and Yuan Zhen, although he soon seized Chi Yin's troops and put them under his own command. Despite Chi Chao's advice that he head directly for Former Yan's capital Yecheng, Huan proceeded slowly, defeating Former Yan's troops repeatedly but taking three months to reach the Yellow River, stoppinging Fangtou (枋頭, in modern Hebi, Henan) -- and again hesitated there at crossing the Yellow River and attacking Yecheng, not far away.

Murong Wei and Empress Dowager Kezuhun were panicking and planning to flee back to the old capital Helong (和龍, in modern Jinzhou, Liaoning), but Murong Wei's uncle Murong Chui the Prince of Wu offered to make one last attempt to resist Huan. Murong Chui and his brother Murong De engaged Huan, dealing him minor losses. Meanwhile, the Jin army's food supply was running out (as a supply plan that Huan put Yuan in charge of was failing in light of the failure to build a canal quickly). Huan began to withdraw, and Murong Chui and Murong De set up a trap for Huan's army, nearly annihilating it. Soon, Former Qin forces, from which Former Yan had sought assistance from, also arrived, and Huan was dealt another major defeat. Huan, humiliated at the greatest defeat in his career, deflected blame by accusing Yuan of being unable to supply food and ordered that Yuan be demoted to commoner status. Yuan, instead of submitting, occupied Shouchun (壽春, in modern Lu'an, Anhui) and rebelled, seeking assistance from both Former Yan and Former Qin.

Against Yuan Zhens clan

With Huan's forces having been severely defeated, Yuan was able to hold Shouchun. He died in spring 370, and was succeeded by his son Yuan Qin. Huan's forces, under his generals Zhu Yao (竺瑤) and Huan Shiqian were able to defeat Former Yan and Former Qin forces sent in aid of Yuan Qin. In fall 370, Huan himself arrived at Shouchun and surrounded it. At that time, Former Yan was under a major attack by Former Qin's prime minister Wang Meng, and Former Yan forces withdrew. After Former Yan fell to Former Qin later that year, Shouchun was in even greater distress. Former Qin relief forces, sent in spring 371, were defeated by Huan. Huan then captured Shouchun and slaughtered Yuan's clan, along with the clan of his supporter Zhu Fu (朱輔).

Removal of Emperor Fei

Huan had long considered seizing the Jin throne, and his original plan had been that if he had been able to destroy Former Yan, he would then return to Jiankang and force the imperial government to confer the nine bestowments on him, and then he could take the throne. Once, he had asked the fortuneteller Du Jiong (杜炅), who had a reputation for accurate prophecies, to see what he could achieve. Du's response was, "Your achievements are as great as the universe, and you will reach the highest rank among imperial subjects." This made Huan rather unhappy, as he hoped to be more than an imperial subject.

After recovering Shouchun, he asked Chi Chao whether the humiliation at the Battle of Fangtou had been removed—and Chi honestly told him that it had not. Instead, they planned an alternate strategy to try to showcase Huan's power—deposing Emperor Fei. Because Emperor Fei had been cautious in his behavior and lacked faults, they decided to spread rumors that Emperor Fei was impotent and unable to bear children—and that his sons, by his concubines Consort Tian and Consort Meng, had in fact been biological sons of men whom he favored, Xiang Long (相龍), Ji Hao (計好), and Zhu Lingbao (朱靈寶). (The rumors also implied a homosexual relationship between Emperor Fei and Xiang, Ji, and Zhu.) He then went to the capital and intimidated Emperor Kang's wife, Empress Dowager Chu, to issue an edict that he had drafted deposing Emperor Fei. Emperor Fei was reduced to the rank of Prince of Donghai, and then further to Duke of Haixi, and put under heavy guard. Huan made his granduncle, Sima Yu, Prince of Kuaiji, emperor (as Jianwen), apparently believing that the easy-going Sima Yu would be easy to control. Meanwhile, he carried out several acts intended to both terrorize imperial officials and to affirm his power—he deposed Emperor Jianwen's brother Sima Xi (司馬唏) the Prince of Wuling, and killed many members of the honored Yin and Yu clans under false accusations of treason. (He wanted to kill Sima Xi as well, but Emperor Jianwen wrote humble letters to him begging for Sima Xi's life, and Huan was unable to insist on Sima Xi's death.)

Hesitation at taking the throne and death

In 372, Emperor Jianwen grew ill, and he issued four successive edits summoning Huan to the capital—a strong indicator that he was willing to yield the throne to Huan—but Huan declined each time, apparently believing that the edicts were a trap. Indeed, Emperor Jianwen initially drafted a will that stated, "The Grand Marshal Huan Wen shall be regent under the precedent of the Duke of Zhou," and "If the child can be assisted, assist him; otherwise, take the throne yourself," mirroring language that Liu Bei, the founding emperor of Shu Han, used when entrusting his son Liu Shan to Zhuge Liang. With Huan not in the capital to affirm it, however, Wang Tanzhi persuaded Emperor Jianwen to tear up the will and rewrite the instructions as, "All major affairs shall be submitted to the Grand Marshal, under the precedents of Zhuge Liang and Wang Dao," greatly reducing any legitimacy Huan might have if he should try to take the throne.

Emperor Jianwen soon died, and was succeeded by his son Sima Yao the Crown Prince (as Emperor Xiaowu). With Huan not in the capital, actual power at the capital soon slipped into the hands of Xie An and Wang Tanzhi, a situation that greatly displeased Huan, who, however, when again summoned by Emperor Xiaowu and Empress Dowager Chu to serve as regent, declined. He did visit the capital in 373, and there was a rumor that he would execute Wang and Xie and then seize the throne. As Wang and Xie greeted him, however, he did not carry out the rumored actions, and after visiting the young emperor, returned to his base at Gushu (姑孰, in modern Ma'anshan, Anhui). He grew ill in fall 373, and, after entrusting matters to his brother Huan Chong, died. His domain was divided into three parts, governed by Huan Chong, another brother Huan Huo, and his nephew Huan Shixiu (桓石秀). As Huan Chong was loyal to the imperial government, the threats of a Huan usurpation dissipated. (When, on his deathbed, Huan Wen was asked by Huan Chong what to do with Wang and Xie, his response was, "They will not let you handle them," meaning that while Wang and Xie were not daring to disobey him while alive, they would not obey Huan Chong after his death, and that killing them would not be helpful to Huan Chong either.) Despite imperial officials' secret happiness that Huan was dead, he was formally buried with great honors.

生平

為父報仇

桓溫出生後還未夠一歲，就被溫嶠稱許，父親桓彞於是以「溫」作為桓溫的名字。年少與殷浩齊名。咸和三年（328年），桓彞在蘇峻之亂中被蘇峻將領韓晃所殺，當時桓彞所駐涇縣的縣令江播亦有協助。桓溫當時極度痛心，且一直想著為父報仇。桓溫十八歲時，江播已死，江播的三名兒子則在守喪，但他們仍有防備桓溫，將刀刃藏在杖中。桓溫則以弔唁為名，得以進入三人守喪的廬屋內，立殺江彪，及後追殺其餘兩人。

出鎮外地

後桓溫娶南康長公主，拜任駙馬都尉，並承襲父爵萬寧男。咸康元年（335年）任琅琊太守。後升輔國將軍。建元元年（343年），桓溫配合征西將軍庾翼的北伐行動，假節任前鋒小督，進據臨淮。三個月後，桓溫升為都督青徐兗三州諸軍事、徐州刺史。永和元年（345年），庾翼病死，臨終前上表求以兒子庾爰之接掌荊州，作為自己繼任者。但輔政的何充則推薦桓溫，桓溫於是於當年獲升任安西將軍，持節都督荊司雍益梁寧六州諸軍事、領護南蠻校尉、荊州刺史，代替庾氏鎮守荊州。

平滅成漢

永和二年（346年），桓溫趁成漢內部不穩，漢主李勢荒淫無道令國家衰弱，決心征伐。當年十一月就上表朝廷，並立刻率領益州刺史周撫、南郡太守譙王司馬無忌和建武將軍袁喬等進攻成漢。當時朝廷內部多數都認為蜀地險要偏遠，而且桓溫兵少而深入蜀境，都為他擔憂。次年三月，桓溫進兵至彭模，並聽從袁喬全軍進擊，只帶三日糧食直攻成都的計謀，只留參軍孫盛和周楚以弱兵在彭模守輜重，桓溫則親自率兵直攻成都。

及後李勢所派抵抗桓溫的將領李福嘗試襲擊彭模，但在孫盛等人奮戰之下被擊退。而桓溫進兵時遇到守將李權，三戰三勝，並一直逼近成都，李勢於是在笮橋率所有兵力抵抗桓溫。桓溫前鋒初時陷於不利，參軍龔護戰死，箭矢更射到桓溫所騎馬匹以前，兵眾十分恐懼而要撤退。但當時戰鼓鼓手卻錯誤擂鼓命兵眾進攻，袁喬於是拔劍領兵與成漢軍激戰，終大敗對方，桓溫於是進攻至成都城下並燒了城門。成漢人見此，再無鬥志，李勢亦乘夜棄城逃至葭萌。不久，李勢決定投降，桓溫受降並遷李勢及成漢宗室到建康。

桓溫平蜀後留駐成都一個月，在當地舉任賢能，表彰美善。又以成漢舊臣譙獻之、常璩等人作為自己參佐，成功安撫當地人民。桓溫即將返回荊州時，隗文、鄧定等人在蜀地叛亂，桓溫與袁喬、周撫等各自領兵討伐，都將對方擊破。後桓溫領兵還鎮江陵（今湖北江陵縣）。

永和四年（348年），朝廷以桓溫平蜀的功勳，升桓溫為征西大將軍、開府儀同三司，封臨賀郡公。

待機掌權

桓溫雖然滅掉成漢，聲名大振，但亦因此令朝廷忌憚他功高不能控制，輔政的會稽王司馬昱於是擢升揚州刺史殷浩處理朝政，以抗衡桓溫日漸增長的勢力。永和五年（349年），後趙君主石虎死，北方因石虎諸子爭位而再度混亂。桓溫見此，即進據安陸，並上疏請求北伐，但久久都沒有回音。至永和六年（350年），朝廷以殷浩為中軍將軍、都督五州諸軍事，委以北伐重任，以此抗衡桓溫。桓溫亦知朝廷以殷浩抗衡自己，感到很不忿，但桓溫亦知殷浩為人，並不憂心。當時桓溫除本官所都督六州外亦加都督交、廣二州共八州，此八州士兵和資源調配都不由朝廷掌握。故此當時桓溫屢次上表請求北伐不果後，再次上表請求北伐並立刻自行率四、五萬兵沿長江東進武昌，便令當時人心驚駭，殷浩亦曾打算辭官迴避，而司馬昱亦要寫信勸止桓溫，終令桓溫退兵回荊州。朝廷及後讓桓溫進位太尉，但桓溫辭讓不拜。

隨後兩年，殷浩都有率兵進行北伐，但沒有成果，反倒屢次戰敗，軍需物資更被略奪殆盡，令朝野怨恨。永和十年（354年），桓溫趁機上奏列舉殷浩罪行，逼使朝廷廢殷浩為庶人。桓溫開始掌權。

三伐中原

桓溫分別於354年、356年及369年發動北伐北方十六國的戰役。但除了第二次北伐成功收復洛陽，其餘兩次皆被擊退，成效不大。

北伐前秦

永和十年（354年）二月，桓溫奏免殷浩後不久便發動第一次北伐，親率步騎四萬餘人進攻武關，水軍直指南鄉（今河南淅川縣滔河鄉），命司馬勳從子午道（秦嶺棧道，通向漢中）進攻以關中地區為根據地的前秦。桓溫後率軍在藍田（今陝西藍田縣）擊破氐族苻健軍隊數萬人，進駐長安東面的霸上，逼使前秦君主苻健以數千人退守長安小城。當地民眾很多都以牛和酒款待桓溫軍，而老人亦感觸得哭泣著說：「沒想過今天還能看到官軍！」然而，桓溫未有聽從順陽太守薛珍所言追逼長安，反待敵自潰。六月，苻雄率所有軍力在白鹿原擊敗桓溫。九月，因桓溫本想收割作軍糧的麥子被秦軍搶先收割，並堅壁清野，令晉軍糧秣不繼，被迫徙關中三千多戶一同撤返江陵。撤軍時更遭前秦軍攻擊，死亡失蹤者數以萬計。

桓溫在北伐期間，王猛曾經前來拜見，並大談當世之事，並署任王猛為軍諮祭酒。桓溫撤退時曾請王猛一同南行，並任命他為高官督護，但王猛沒有跟隨。

收復洛陽

永和十二年（356年）三月，桓溫打算發動第二次北伐，請求移都洛陽，修復園陵。雖然桓溫上奏十多次都不被允許，但朝廷卻拜桓溫為征討大都督，督司、冀二州諸軍事，主征討之事。七月，桓溫從江陵起兵發動第二次北伐。八月，桓溫進軍洛陽以南的伊水，當時羌人姚襄正在圍攻洛陽，見桓溫攻來，於是撤去洛陽的圍城軍隊去抵禦桓溫。桓溫終在伊水大破姚襄，姚襄逃走。及後，據有洛陽的周成獻城向桓溫投降，桓溫於是成功收復故都洛陽。桓溫及後拜謁各皇陵及修復其中已被毀壞者。桓溫留穎川太守毛穆之、河南太守戴施等守護洛陽，自己則領三千多家歸降的人民南遷至長江、漢水一帶，返回荊州。昇平四年（360年），桓溫進封南郡公。

隆和元年（362年），前燕將領呂護進攻洛陽，桓溫派庾希及鄧遐助陳祐守城。桓溫亦上奏請求晉室遷都洛陽，又建議南遷的士族返鄉，朝廷畏懼桓溫，不敢有異議；但士族們卻已安於南方，根本不願北返。在此憂慮之時，揚州刺史王述認為桓溫只是以遷都之名威壓朝廷，並非真心想還都洛陽，只要表示順從便可，毋須實行。詔書下達後，晉室始終沒有還都洛陽。

興寧元年（363年），桓溫獲加授侍中、大司馬、都督中外諸軍事、錄尚書事、假黃鉞。次年，桓溫率水軍移守合肥，朝廷改以桓溫為揚州牧、錄尚書事，並兩度徵桓溫入朝。桓溫在第二次徵召時才入朝，行至赭圻時停止並留駐當地。當時前燕又再進攻洛陽，守將陳祐留兵出奔。司馬昱知道後，於是於興寧三年（365年）與桓溫商議征討之事，並讓桓溫移鎮姑孰。但同年因晉哀帝死，征伐之事就暫停。同年，前燕攻陷洛陽。

北伐前燕

太和四年（369年），桓溫為了樹立更高的威望，發動第三次北伐，並請與徐、兗二州刺史郗愔、江州刺史桓沖及豫州刺史袁真等一同討伐前燕。而桓溫其實一直都希望控制郗愔在京口（今江蘇鎮江）所統領的精兵，郗愔子郗超時為桓溫參軍，便修改了父親寫給桓溫的書信，變成以老病辭任二州刺史職位，並勸桓溫接掌自己所領軍隊。桓溫看信後十分高興，桓溫亦因而得以自領徐、兗二州刺史。及後，桓溫正式起兵，率五萬人從姑孰出發北伐。

桓溫前進至金鄉，因大旱引水讓水軍舟船得以進入黃河。當時郗超認為如此難以運輸補給，建議直攻前燕都城鄴城，或者停駐黃河、濟水一帶管理漕運，積聚足夠的物資待次年夏天才進攻。但桓溫都沒有聽從。桓溫派軍先後攻敗湖陸守軍、在黃墟迎擊的慕容厲和林渚的傅顏，前燕於是向前秦求救，桓溫亦前進至枋頭。桓溫及後沒有再進逼前燕，反希望以持久戰坐取全勝。九月，因袁真無法開通石門以通水路運輸，而前燕亦斷了桓溫糧道，桓溫見戰事不利而糧食又已盡，更聽聞前秦援兵將至，於是燒船、棄輜重鎧甲，自陸道撤退。途中遭前燕騎兵追擊，損失三萬餘人；更被前秦軍在譙郡擊敗，於是這次北伐以大敗告終。

廢帝立威

桓溫北伐後，命人修築廣陵城池並移鎮當地。又因北伐失敗而感到十分羞恥，並將罪責推給未能開通石門水道的袁真。袁真不甘心被桓溫誣以罪責，而上奏桓溫罪狀又不果，於是以壽春（今安徽壽縣）叛歸前燕。同年袁真逝世，太和六年（371年），桓溫率軍擊敗前秦援軍，並攻陷壽春，俘斬袁真子袁瑾。

桓溫雖然自從363年獲錄尚書事開始就幹預朝政，而且自負有才能，早就有異志，所以才發起北伐希望先建功勳，然後領受九錫並進圖篡位。但因第三次北伐遭前燕及前秦擊敗，聲名和實力都減弱，圖謀不成。壽春被桓溫攻下後，參軍郗超知道桓溫的心意，於是建議廢立之計而加強桓溫聲威。桓溫亦早有此謀，於是在當年便廢晉廢帝司馬奕為東海王，改立司馬昱為帝，即晉簡文帝，自己以大司馬專權。

多所廢徙

桓溫隨後就因厭惡殷氏和庾氏強盛，又忌憚時任太宰的武陵王司馬晞的軍事才幹，於是先上奏彈劾司馬晞「聚納輕剽，苞藏亡命」，並誣司馬晞將成叛亂禍根，成功將司馬晞及其子司馬綜免官。及後又派弟弟桓祕逼迫新蔡王司馬晃誣稱自己與司馬晞、司馬綜、著作郎殷涓、太宰長史庾倩、太宰掾曹秀、散騎常侍庾柔等人謀反。桓溫下令將他們收付廷尉，晉簡文帝只有哭泣。後在桓溫意願下，廷尉上奏要賜死司馬晞，簡文帝不願，下詔要再作議論。桓溫於是上書請誅司馬晞，言辭十分嚴厲急切。簡文帝見此，只得寫書給桓溫：「若果晉室國祚長久，那麼你就應該依從早前的詔命從事；如晉室大勢已去，那你就讓我退位讓賢吧。」桓溫見後，流汗色變，而司馬晞亦只被廢為庶人，未被誅殺。但庾柔、殷涓等人都被族誅。桓溫此後，威勢極盛，連謝安見他亦對他遙拜，更以君臣稱作二人關係，足見當時桓溫權勢已經比皇室更高，如同君主。

未得九錫

次年，簡文帝死，死前遺詔由桓溫輔政，如司馬懿、王導的先例。當時群臣都因桓溫權勢而不敢以皇太子司馬曜為帝，反等待桓溫的決定。尚書僕射王彪之則以太子即位之正當性釋除群臣疑慮，迎司馬曜繼位為晉孝武帝。桓溫原本寄望簡文帝會將帝位禪讓給自己，或讓自己倣效周公為君主主理朝政。如今兩者皆否，大失所望，因而十分怨憤，更懷疑這是王坦之、謝安做的。不久，朝廷下詔桓溫入朝輔政，並加前部羽葆鼓吹，武賁六十人，桓溫辭讓。寧康元年（373年），桓溫入朝拜山陵，朝廷詔謝安及王坦之到新亭迎接桓溫，百官拜於道側。因著桓溫兵權，其時有名望地位的官員們都很害怕，更有桓溫將要殺害王坦之及謝安的傳言。三月，桓溫患病，停建康十四日後退還姑孰。當時桓溫表示想受九錫，多番催促，而王彪之及謝安見桓溫病重，則借修改袁宏所寫的錫文暗中拖延。七月己亥日（8月18日），桓溫逝世，享年六十二歲，至此錫文仍未完成。朝廷追贈丞相，諡號為宣武。喪禮依司馬孚、霍光的儀式，葬姑孰青山。

性格特徵

• 桓溫少時有豪邁風氣。姿貌甚偉，面有七星。

• 桓溫伐蜀時經過長江三峽，部隊中有人捉了一隻小猿，母猿則在岸邊哀號，一直跟了桓溫的船隊行了百多里。及更跳了上船，但隨即就死了。及後有人剖開其腹，見其腸臟都斷成很多小段。桓溫知道後大怒，貶黜了捉了小猿的人。又一次，桓溫與眾人一同吃飯，一名參軍用筷子夾蒸薤菜時，薤菜秥在一起夾不起，而其他同桌的人又不幫助，看見參軍夾著不放的模樣更笑起來。桓溫見此，說：「一同吃飯仍不相助，何況遇到危難時呢？」於是將他們免官。都見到桓溫雖然是極具野心的將領，但亦能在小事上顯出顧及人情的性格。

• 桓溫性格儉樸，每次宴會只吃七個奠柈茶果。

• 桓溫每逢大事無靜氣。既要行伊霍之事，又慮太后意異（褚蒜子時為崇德太后），等待時「悚動流汗，見於顏色」（《晉書·后妃傳》）。太后禮佛畢，從容作答，桓溫又大喜過望。

軼事

• 桓溫因晉成帝姊南康公主而大貴，及掌軍權，盡廢明帝後人。簡文帝說，找郎婿找得王敦、桓溫輩，稍得志便要廢立人。

• 桓溫待南康公主寡仁義。行軍司馬謝奕為人狂放，醉後窮追不捨，桓溫只得到處逃竄。南康公主見之，訴曰：「非是狂司馬，安得見郎君。」

• 桓溫與弟桓沖志趣不合，情誼頗深。溫死，沖為國家故，立其幼子玄。

• 桓溫年少家貧，與人玩摴蒱曾大敗，要找袁耽求取勝之法。

• 有人曾問桓溫有關謝安及王坦之的優劣，桓溫正想說，但就後悔說：「卿喜傳人語，不能復語卿。」

• 桓溫第三次北伐時，行軍至金城，看到自己任琅邪太守時所種的柳樹已經十分粗大，慨嘆：「木猶如此，人何以堪。」於是扶著枝幹，拿著枝條，流下眼淚。

• 桓溫曾躺臥著說：「作此寂寂，將為文、景所笑。」然後起坐，又說：「既不能流芳後世，亦不足復遺臭萬歲邪？」。又曾經在經過王敦墓，說：「可人，可人！」

• 桓溫自以雄姿風氣是司馬懿、劉琨之流，若有人將他比作王敦就會很不高興。第一次北伐後，在北方獲得了一個老婢，是昔日劉琨的女伎。老婢見桓溫後就掩面哭泣，桓溫追問，老婢則答：「你很像劉司空大人（劉琨）。」桓溫聽後十分高興，便去整理衣冠，及後又召來老婢來問。老婢則說：「脣很像，但可惜太薄；鬚很像，但可惜是赤色；體形很像，但可惜太矮；聲音很像，但可惜不雄壯。」桓溫聽後脫下冠帶去睡，不高興了數日。

• 桓溫一次乘下雪打獵，先見王濛、劉惔等人。劉惔見他一身戎裝，問：「老賊欲持此何作？」桓溫說：「我若不為此，卿輩那得坐談？」

• 桓溫曾讀皇甫謐的《高士傳》，讀到於陵仲子時就擲去書本，說：「誰能這樣苛刻對待自己！」

評論

• 《晉書》評：「桓溫挺雄豪之逸氣，韞文武之奇才，見賞通人，夙標令譽。時既豺狼孔熾，疆場多虞，受寄扞城，用恢威略，乃踰越險阻，戡定岷峨，獨克之功，有可稱矣。及觀兵洛汭，修復五陵，引斾秦郊，威懷三輔，雖未能梟除凶逆，亦足以宣暢王靈。既而總戎馬之權，居形勝之地，自謂英猷不世，勳績冠時。挾震主之威，蓄無君之志，企景文而概息，想處仲而思齊，睥睨漢廷，窺覦周鼎。復欲立奇功於趙魏，允歸望於天人；然後步驟前王，憲章虞夏。逮乎石門路阻，襄邑兵摧，懟謀略之乖違，恥師徒之撓敗，遷怒於朝廷，委罪於偏裨，廢主以立威，殺人以逞欲，曾弗知寶命不可以求得，神器不可以力征。豈不悖哉！豈不悖哉！斯實斧鉞之所宜加，人神之所同棄。然猶存極光寵，沒享哀榮，是知朝政之無章，主威之不立也。」

• 庾翼：「桓溫少有雄略，願陛下勿以常人遇之，常壻畜之，宜委以方召之任，託其弘濟艱難之勳。」

• 何充：「桓溫英略過人，有文武識度。」

• 孫綽：「高爽邁出。」

• 劉惔：「鬚如反蝟毛，眼如紫石稜，自是孫仲謀、司馬宣王一流人。」

家庭

父母

• 桓彞，東晉宣城內史，蘇峻之亂時因反抗蘇峻而遇害。

• 孔憲，獲追贈臨賀太夫人。

妻妾

• 司馬興男，桓溫正妻，南康公主，晉明帝女。

• 李氏，李勢妹，一說為李勢女。桓溫平蜀後納為妾。

• 馬氏，桓玄之母，後追贈為豫章公太夫人。

兄弟

• 桓雲，桓溫二弟，官至江州刺史。

• 桓豁，桓溫三弟，東晉將領，官至征西大將軍。

• 桓祕，桓溫四弟，官至輔國將軍、宣城內史。桓溫臨死時與桓溫子桓熙和桓濟合謀殺死將接掌桓溫兵眾的桓沖。事敗後被朝廷棄用。

• 桓沖，桓溫幼弟，有武幹，受桓溫器重。官至車騎將軍。

子女

• 桓熙，桓溫長子，初被立為世子，但因才能不高，桓溫將兵眾都交給桓沖。桓溫臨死時曾與桓濟和桓祕謀殺桓沖，失敗後被徙至長沙。

• 桓濟，與桓熙謀殺桓沖失敗，被徙至長沙。

• 桓歆，封臨賀公。

• 桓禕，愚笨，五榖不分。

• 桓偉，東晉將領，官至安西將軍、領南蠻校尉、荊州刺史、使持節督荊益寧秦梁五州諸軍事。

• 桓玄，桓溫幼子，襲桓溫爵。東晉官至相國，後篡位建立桓楚。最終被劉裕所主持的討伐軍擊敗並被殺。

• 桓伯子，桓溫二女，嫁王愉。

• 桓氏，桓溫女，嫁王裕之。