姚苌立国384正月，前燕降将慕容垂率先招降纳叛，重建后燕，大举反叛；慕容泓与弟弟慕容冲趁火打劫，相继起兵建立西燕。苻坚的第四子苻睿奉诏平叛，姚苌随苻睿征讨慕容泓。慕容泓素来惧怕勇猛果敢的苻睿，“闻其至也，惧，率众将奔关东。”苻睿好大喜功，恃勇轻敌，闻讯急令紧咬追击，以一举全歼。姚苌极力谏阻：“鲜卑族早有回归故土之心，理应顺水推舟驱使他们出关，前往不可截击，以免他们狗急跳墙，与我军同归于尽！”苻睿立功心切，对姚苌的建议置若罔闻，逼令劳师远征的军士们连续作战，长途奔袭截击慕容泓部。军士们因其向来“不恤士众”，早已满腹怨恨。慕容泓见出关后路被截断，急红了眼，困兽犹斗，发动鱼死网破的反击战。双方展开激战，“睿败绩，被杀。”姚苌心怀愧疚，派使者向苻坚说明实情并主动请罪。苻坚痛失爱子，“大怒”，斩杀使者泄愤。姚苌由此“惧诛，遂叛”，慌不择路“奔于渭北”。当地众豪族素来敬畏姚苌，“咸推苌为盟主”，力谏姚苌“趁秦亡之兆已见”时自立为王。在拥有“北地、新平、安定羌胡降者十余万户”后，姚苌自称大将军、万年秦王，改元白雀，史称后秦。（弑杀）苻坚苻坚得知姚苌自立为王且进驻北地（今陕西耀县东南），亲自“率步骑二万讨姚苌。”姚苌被截断后路，断绝运水之路，“苌众危惧，人有渴死者。”就在苻坚企图趁姚苌部队渴得嗓子冒烟时一举全歼之际，姚苌军营中突降暴雨，“营中水三尺”，姚苌部队喝足了水，顿时军心大振。姚苌趁机联合慕容泓，“率众七万来攻坚”，将俘获的前秦将领“数十人，皆礼而遣之。”姚苌围困新平，新平太守苟辅“凭城固守。”双方展开地道战和阵地战，“苌众死者万有余人。”姚苌见苟辅“粮竭矢尽，外救不至，”便派使者入城欺骗苟辅：“我只想在新平城建立根据地，绝不会滥杀无辜。您现在弹尽粮绝，走投无路。我以人格担保，放您和城中百姓回长安。”苟辅轻信他的承诺，“率男女万五千口出城。”姚苌把他们“围而坑之，男女无遗。”苻坚不敌西燕慕容冲，留下太子固守京城长安，自己率部逃往五将山。姚苌闻讯，令部将围困苻坚，将其带回新平。在逼取国玉玺和强迫苻坚禅让无果后，姚苌将其弑杀。苻坚被弑杀后，其子苻丕即位不久，就因兵败被杀。苻坚的族孙苻登即位，大举讨伐姚苌。两军对垒厮杀，“累战互有胜负。”姚苌攻破始平郡，抓获太守徐嵩。徐嵩宁死不降，怒斥“汝姚苌罪该万死！”徐嵩英勇就义后，部下全部被活埋。姚苌因伤亡惨重，气急败坏，认定苻坚是罪魁祸首，竟然丧心病狂令部下“掘苻坚尸，鞭挞无数”，甚至剥去尸体上的衣物，用荆棘裹着尸体丢入坟墓中。做了亏心事，就怕鬼叫门，掘墓鞭尸后，姚苌屡战屡败，认为前秦军有苻坚的神灵相助，竟在军营中供奉苻坚画像并祈祷。姚苌在祈祷中，将弑君行为全部推到死去多年的哥哥姚襄头上。他表示，自己从未忘记苻坚加封龙骧将军一事，恳求“陛下勿追计臣过也！”可是，姚苌“自立坚神象，战未有利，军中每夜惊恐。”姚苌在创建了后秦国家后，羌族姚苌一共在位九年。姚苌的父亲就是羌族的领袖人物，他是父亲的第24个儿子。姚苌之所以可以建立国家被拥护为皇帝，这和他个人能力有很大关系。姚苌从小就表现出他足智多谋的一面，而且也十分聪颖。只是他小时候在哥哥们眼里还是有些奇怪的，因为他从来不认真学习，只做一些在别人眼里看来很独特的事情。在姚苌长大后便开始出征，起初是很不顺利的，姚苌跟随着哥哥姚襄出兵，可是因为中了敌人的圈套，哥哥被杀掉了，姚苌没有办法只能向敌方投降。之后姚苌开始为前秦做事，他多次出征名声逐渐大了，在讨伐敛岐的时候，对方听到姚苌也来了，马上就都投降了，由此可以看出姚苌的威慑力已经有了很大的提高。而姚苌被噩梦吓死是有具体原因的，因为姚苌当上皇帝并不是那么光明正大，他是把自己之前服侍的主子姚坚杀掉后才当上皇帝的。而且姚苌也知道自己的做法很不人道，即便已经当上皇帝了，可他的内心依旧是十分害怕的，毕竟做了一件很亏心的事情。正是因为这件事长期萦绕在他的脑海中，姚苌在晚上经常会做噩梦，做噩梦并不是就一次两次，而是长期的做噩梦，这使得姚苌的神经一直是紧绷的。噩梦对姚苌的影响逐渐加深，使得他进入一个癫狂状态，最后噩梦所带来的消极影响在长期的积压后，达到一定程度便爆发出来，终于姚苌因为内心恐慌害怕而去世了，简单说就是被噩梦吓死了。他之所以长期被噩梦缠绕还是因为他用非正当手段把前秦的皇帝杀死了。通过姚苌做噩梦一事可以看出他还是有点良心的，只是因为自己胆小，没有承认错误的勇气导致他仍然被噩梦缠绕，因为有的人即便做坏事还能表现的和常人一样。但姚苌知道自己做错事，他的内心不能将此事释怀，所以只要一闲下来，他就会内心自责自己，晚上睡觉中这种意识还会表现出来，逐渐这个意识就摆脱不掉了，他越想越害怕，这种意识长时间积累所产生的影响就是整个人不能在像正常人一样，他满脑子都是这件事，直到癫狂状态，这所面临的结局就是自己被自己吓死。所以历史上便有姚苌被噩梦吓死的说法。姚苌是后秦的皇帝，而毛皇后是前秦的皇后。提到姚苌与毛皇后的关系，可以用势不两立来形容。因为他们之间所代表的利益是不同的，毛皇后是中国历史上十六国中前秦的皇后，而姚苌则是推翻前秦政权并创立后秦的皇帝。姚苌和毛皇后之间的联系就发生在前秦灭亡，后秦建国期间。因为前秦军队在之前的战争中取得了胜利便放松了警惕，结果姚苌就率领军队前去偷袭，因为发生在夜晚而且前秦军队兵力也不多，很快便被姚苌的军队侵入了，毛皇后即使带领军队顽强反抗也无济于事。在这场战斗结束后，毛皇后也就成为了俘虏。姚苌的军队是十分高兴的，因为他们俘获的毛皇后是一位很美丽的女子，还把毛皇后带回到了他们的军营中，在这个阶段，毛皇后受尽了士兵对他的凌辱，最后她还被捆绑着送到了姚苌那里。此时的毛皇后已经彻底没有形象了，她头发凌乱，身体还很脏，美貌瞬间消失殆尽。可是姚苌知道她的美貌，便主动提出来要毛皇后当他的妃子，毛皇后一身正气，坚决不接受姚苌的条件，反而还把姚苌痛骂了一顿，来表达她对前秦的忠心。即便如此，姚苌还是不死心，任凭毛皇后怎样骂他，他也没有给毛皇后用刑。只是最后，毛皇后还是要誓死表达衷心，姚苌看到了此番情景知道自己的这个想法也不会实现了，于是便把毛皇后拖出去斩首了。毛皇后驾崩时，年仅21岁。之后，前秦军连战连捷，姚苌也巧使计谋扳回几局。双方势均力敌，陷入艰苦的拉锯战。最后，姚苌因病情加重，退守安定（今甘肃中部）。姚苌病重期间，精神更加恍惚，时常出现幻觉。他常做“（苻坚）将天官使者、鬼兵数百突入营中”来索命的噩梦，吓得魂不守舍、夜不能寐。一天夜里，他又梦见苻坚索命，被惊醒后跳下病床在宫中躲避，并令侍卫刺杀围绕在他身边的索命厉鬼。侍卫们向不存在的敌人发动攻击时，锋利的兵刃“误中苌阴，出血石余。”姚苌紧急托孤后，不治身亡，时年64岁。乱世英雄起四方，有枪就是草头王。姚苌在最初失败时无奈归顺苻坚，时来运转时另立山头，凭“多权略”与“善御人”，在乱世中创立一番基业，原本无可厚非。何况，姚苌在位期间，笼络重用人才，兴建太学，整顿刑律，提倡节俭，惩治贪腐，作为一国之君，也算差强人意。
In the first month of the year, MuRongchui, the former Chang Chang of Yan, took the lead in recruiting andaccepting the rebellion, reestablished the Back Yan, and rebelled on a largescale. Murong Hong and his brother Murong chong, have set up west Yan. FuJian's fourth son Fu Rui gave an imperial order to calm the Fu, and Yao Changreturned with him to take over Murong Hong. Murong Hong had always been afraidof the brave and decisive Fu Rui, "given his arrival, he feared that hewould head for Kanto with all his friends". Pleased with the success, FuRui made light of the enemy and gave a hasty order to give chase to the latterin order to complete the blow. Yao CHANG strongly ADVISE him, "The XianBEIPEOPLE HAVE LONG HAD the heart to return to THEIR native land, SO THEY SHOULD BEDRIVEN OUT OF CHANG CHANG AND BE RETURNED TO CHANG Chang Chang Chang ChangChang Chang Chang Chang Chang Chang Chang Chang Chang Chang Chang Chang ChangChang Chang Chang Chang Chang Chang Chang Chang Chang Chang Chang Chang ChangChang Chang Chang Chang Chang Chang Chang Eager to give the facts, Fu Ruiturned a deaf ear to Yao Chang's advice and forced the returning officers toconduct a continuous war and a long distance raid to volleys Murong Hong'sheadquarters. The sergeants were already full of resentment for their"lack of respect". Murong Hong see the back of the cut off, red eyes,trapped animals still fight, launch the counter-attack. The two sides launcheda fierce battle, "Rui defeat, was killed." Feeling guilty, Yao Changsent an envoy to explain the truth to Fu Jian and offered to apologize to him.Fu Jian, suffering from the loss of his beloved son, was "furious"and killed the messenger to vent his anger. As a result, Yao Chang "wasafraid to be disarmed, so he mutated" and rushed to Weibei in a hurry. Thelocal nobles have always respected Yao Chang, "Xian Chang as thechampion", and remonstedYao as the king "when the omen of the demiseof Qin has been seen". After owning "North land, Xinping, stableQiang Hujiang more than ten thousand households", Yao Chang self-styled asa general, king of Qin ten thousand years, changed to be white Sparrow in Yuan,and was called Post-Qin in history. When Fu Jian learned that Yao Chang hadestablished himself as king and stationed himself in the north land (southeastof today's Yao-County, Shaanxi Province), Fu Jian personally "rode twentythousand men at a rate to ask Yao Chang". "Allow Yao to be chang, cutoff the road to water," allow people to be afraid, and be thirsty. When FuJian planned to wipe out Yao Chang's army while his throat was smoking withthirst, a rainstorm occurred in the Yao Chang army and "there was threefeet of water in the camp". When Yao Chang's army drank enough water, itwas greatly inspired at once. Yao Chang took the opportunity to unite withMurong Hong, "led 70,000 Chang troops to attack", and "dozens ofcaptured former Qin generals were respectfully sent away". Yao Changbesieged Xinping, and the governor of Xinping, Gos Fu, "firmly defended bythe city." Both sides began tunnel warfare and positional warfare,"the dead men were more than ten thousand men." Yao Chang Goufu sawthat "food is exhausted and there is no way to help him", so he sentan envoy to the city to deceive him, "I only want to set up a base inXinping City, I will not allow innocent people to be killed. You're out ofammo. You're out of options. I will release you and the people of the city backto Chang 'an on my honor." Gou Fu believed his promise and "led 5,000men and women out of the city." Yao Chang them "surrounded by men andwomen." Fu Jian was defeated by his father, who was a leader of the Qiangnationality. Yao Chang can be allowed to establish a country and be supportedas an emperor, which has a lot to do with his personal ability. Yao Chang hadshown that he was resourceful and intelligent when he was young. But he wasstrange in the eyes of his brothers when he was young, because he never studiedhard and only did things that seemed unique to others. When Yao Chang was grownup, he returned to the army. At first, it was not smooth. Yao Chang went backto the army with his brother Yao Xiang, but his brother was shot back becausehe was allowed to be planted by the enemy. Later on, Yao Chang began to workfor the Former Qin Dynasty and his reputation grew as a Chang on manyexpeditions. When opposing Chang Chang, they all surrendered immediately, whichshows that Yao Chang's influence had been greatly improved. There is a reasonwhy Yao Chang was changed to death by the bad dream, because Yao Chang was notallowed to be allowed to be emperor, he had murdered his master Yao Jian, whohe had been serving. Moreover, Yao Chang also knew that his behavior was veryinhumane. Even if he had been an emperor, he was still very afraid because hehad done something that he felt bad about. It is this Chang Yao Chang that hasthis back in his mind for a long time that Yao Chang has nightmares at night,not only once or twice, but for a long time, which allows him to be takings. Thenegative influence of the bad dream back to Yao Chang grew stronger andstronger, allowing him to be allowed to go into a state of mania. At last, thenegative influence brought about by the bad dream back to a certain extentafter a long period of accumulation, Yao Chang died as a result of his panicand fear, in short, being scared to death by the bad dream. He was haunted bynightmares because he had killed the former Qin emperor by unfair means. YaoChang having a bad dream can be seen that he is still a bit of a good man