Eastern Wei's territorial size and military strength was far stronger than Western Wei's, and Gao made a number of attempts to try to end the division by conquering Western Wei, but the battles largely proved to be inconclusive, allowing Western Wei to stand. Periodically, Western Wei generals who had prior relationships with Gao would defect to Eastern Wei, and Gao at times carried out campaigns deep within Western Wei territory. However, Western Wei was able to portray Gao as a renegade general who expelled the emperor, and often during campaigns, local populace would assist Western Wei troops because they believed Western Wei's characterization. During this period, Gao also tried to foster harmony between the ethnic Xianbei and Chinese, persuading the Xianbei that they needed the Chinese to practice agriculture to be fed, and persuading the Chinese that they needed the Xianbei's military aptitude to protect them. He saw Emperor Xiaowu's flight as a blot on his personal history, so he treated Emperor Xiaojing with great formal respect, deferring to Emperor Xiaojing in all public occasions. in spring 535, Gao Huan learned that around the new year 535, Emperor Xiaowu, who had a falling out with Yuwen Tai over Yuwen's refusal to condone his
incestuous relationships with his cousins, had been poisoned to death by Yuwen. Gao suggested that an official mourning period be held for Emperor Xiaowu, and while there were disagreements, eventually a mourning period was held. Also in spring 535, a sex scandal affected Gao's household. Gao's
heir apparent Gao Cheng, born of his wife
Princess Lou, had an affair with Gao Huan's
concubine Zheng Dache (鄭大車), and the affair was discovered. Gao Huan caned Gao Cheng and put him under house arrest, and refused to meet with Gao Cheng's mother Princess Lou. He also considered replacing Gao Cheng as heir apparent with Gao You (高浟), the son of his concubine
Erzhu Ying'e, the daughter of
Erzhu Rong who had previously been Emperor Xiaozhuang's empress. After intercession by Gao Huan's friend Sima Ziru, who reminded him how much Princess Lou had done for him before he had accomplished great things and who used violent methods to force the servant girls who were witnesses to the affair to recant, Gao Huan calmed down and did not replace Gao Cheng. Around the new year 536, Gao Huan tried to make an alliance with
Rouran against Western Wei, by marrying a princess to Rouran's Chiliantoubingdoufa Khan
Yujiulü Anagui. However, Yujiulü Anagui soon took a Western Wei princess as consort as well, and the alliance did not materialize. In spring 536, Gao made a deep incursion into Western Wei territory, capturing Xia Province (夏州, roughly modern
Yulin,
Shaanxi), while also rescuing his ally Cao Ni (曹泥) the governor of Ling Province (靈州, roughly modern
Yinchuan,
Ningxia), who had been trapped behind Western Wei lines. The Western Wei general Moqi Pu (万俟普), his son Moqi Shouluogan (万俟受洛干), and other generals Chigan Baole (叱干寶樂) and Poliuhan Chang (破六韓常), who were stationed in the western Western Wei territory, also joined Gao and returned to Eastern Wei with him. Also in spring 536, Gao Huan, at Gao Cheng's request, made Gao Cheng the Eastern Wei prime minister, despite the fact that Gao Cheng was only 14 at this point. Gao Cheng was sent to Yecheng, and he took over actual reign of the Eastern Wei imperial government. The
Volcanic winter of 536 had led to famine in the
Guanzhong region that year; Easterrn Wei also suffered from the volcanic winter, with hailstorms and drought across multiple commanderies in autumn 536. In spring 537, Gao Huan launched a major attack three-pronged on Western Wei, commanded by himself and his key generals
Dou Tai and
Gao Aocao, intending to draw Yuwen's troops to himself while having Dou advance deep into Western Wei territory. Yuwen, pretending to be ready to abandon Chang'an to withdraw to modern eastern
Gansu, instead launched a surprise attack on Dou's troops, slaughtering most of them. Dou committed suicide. Gao Huan and Gao Aocao were forced to withdraw. In counterattacks, Western Wei took modern western
Henan and southwestern
Shanxi. In winter 537, after hearing news that the
Guanzhong region, the heart of the Western Wei state, was suffering from a major famine, Gao Huan launched another major attack on Western Wei. He encountered Yuwen at the
Battle of Shayuan (沙苑, in modern
Weinan,
Shaanxi), and, believing that he had overwhelming numerical advantage, rejected the strategy of Hulü Qiangju (斛律羌舉) to bypass Yuwen and make a direct attack on Chang'an, and his own initial inclination to set fire to the grass fields at Shayuan to have it burn Yuwen's troops, instead directly engaging Yuwen in battle. Yuwen's troops, however, fought hard, one of Yuwen's key generals
Li Bi, led about 600 elite cavalry, charged through Gao's 200,000 soldiers and broke their formation. They defeated Gao's troops, forcing Gao to withdraw. In light of his defeat, the southern provinces and Luoyang area largely rebelled and declared allegiance to Western Wei, but in spring 538 Gao sent
Hou Jing against the southern provinces, recapturing them. In 538, after
Emperor Wen of Western Wei married Yujiulü Anagui's daughter as his empress, Yujiulü Anagui cut off relations between Rouran and Eastern Wei. In fall 538, Gao Huan, assisted by Hou Jing and Gao Aocao, put Luoyang under siege. Yuwen and Emperor Wen led the Western Wei troops to aid Luoyang's defender, the general
Dugu Xin, and a largely inconclusive battle with heavy losses on both sides occurred—with Western Wei being able to kill Gao Aocao, and Yuwen nearly killed in the battle as well. However, eventually Western Wei troops were forced to abandon Luoyang and withdraw, and at the same time, the Eastern Wei general Zhao Qingque (趙青雀), who had been captured by Western Wei in the Battle of Shayuan, rebelled against Western Wei at Chang'an, forcing the Western Wei officials who remained in Chang'an to escort the
crown prince Yuan Qin out of Chang'an. However, Gao Huan was unable to take advantage of the disturbance that Zhao caused, and Yuwen was able to return to Chang'an to suppress Zhao's rebellion. Meanwhile, Western Wei also recaptured some of the southern provinces. For the next few years, while there continued to be border battles, no major campaigns was initiated by either Eastern Wei or Western Wei. In summer 539, Gao Huan gave his
second daughter to Emperor Xiaojing in marriage as Emperor Xiaojing's wife and empress. In winter 541, Gao Huan had Emperor Xiaojing issue an edict standardizing measurement units for cloth, to avoid the populace's being unfairly taxed. In winter 542, Gao Huan launched a major attack on the Western Wei border city of Yubi (玉壁, in modern
Yuncheng,
Shanxi), but the Western Wei defence was held successfully and Gao was forced to withdraw. In spring 543, another sexual wrongdoing by Gao Cheng would lead to a new campaign between Eastern Wei and Western Wei. The official Gao Zhongmi (高仲密, Gao Aocao's brother), already fearful over his situation because one of Gao Cheng's major assistants, Cui Xian (崔暹), had tried to pick his faults after he divorced Cui Xian's sister, was further aggravated when Gao Cheng tried to rape his second wife, Li Changyi (李昌儀). He therefore surrendered the important garrison of Hulao (虎牢, in modern
Zhengzhou,
Henan) to Western Wei. Yuwen led his troops to try to come to Gao Zhongmi's aid and further again seize the entire Luoyang region, but was repelled in a major battle near Luoyang, during which both Yuwen and Gao Huan were nearly killed in battle, with Heba Sheng, then a Western Wei general, nearly killing Gao with a spear. (In retaliation, Gao Huan later had all of Heba's sons who remained in Eastern Wei territory executed.) By summer 543, the Western Wei forces had withdrawn, and the entire Luoyang region was again under Eastern Wei control. in 544, with Gao Huan believing that four key officials who were close to him—Sun Teng, Sima Ziru, his cousin Gao Yue (高岳), and his sworn "brother" Gao Longzhi (高隆之) -- were wielding too much power, he gave the 22-year-old Gao Cheng additional authorities, and Gao Cheng increasingly asserted authorities over these officials and others. For example, once when Sun visited Gao Cheng but was acting insufficiently deferentially, Gao Cheng had his attendants throw Sun on the ground and pound him with the sword hilts. Gao Cheng also made one of his close assistants, Cui Jishu (崔季舒, Cui Xian's uncle) an assistant to Emperor Xiaojing, in order to keep a closer eye on Emperor Xiaojing. Gao Cheng soon greatly enhanced the authorities of both Cui Xian and Song Youdao (宋遊道) and charged them with the responsibilities of stamping out corruption among officials—which Gao Huan himself had been reluctant to do so. Based on Cui Xian's and Song's recommendations, Sima was arrested and reduced to commoner rank, while
Yuan Tan (元坦) the Prince of Xianyang was relieved of all governmental posts. In spring 545, Erzhu Ying'e's brother Erzhu Wenchang (爾朱文暢) and Zheng Dache's brother Zheng Zhongli (鄭仲禮), along with Ren Zhou (任冑), conspired to assassinate Gao Huan and support Erzhu Wenchang as leader, but the conspiracy was discovered, and the conspirators were put to death, along with their families. However, because of Gao Huan's favors for Erzhu Ying'e and Zheng Dache, he spared their brothers.
Lou Zhaojun supported and assisted Gao Huan when he married more women, wanting to expand his power. In fall 545, due to an alliance between Western Wei and Rouran to attack Eastern Wei, Gao Huan sued for peace with Rouran by requesting a marriage between a daughter of Yujiulü Anagui and Gao Cheng. Yujiulü Anagui refused, stating that it would only be sufficient if
Gao Huan himself married her. Gao Huan himself initially refused, but
Princess Lou, Gao Cheng, and Wei Jing all persuaded him otherwise, and he married Yujiulü Anagui's daughter, referring to her as the
Princess Ruru. To facilitate this marriage, Princess Lou moved out of the mansion, but Gao Huan and Princess Lou were not formally divorced. In fall 546, Gao Huan launched another major attack on Western Wei, apparently to make one final attempt to destroy it. He put Yubi under siege, intending to attract Western Wei forces to Yubi in order to destroy it, but Western Wei did not respond. Yuwen' Chinese general in charge of defending Yubi,
Wei Xiaokuan, however, defended against all kinds of siege tactics that Gao Huan tried, for 50 days, and Eastern Wei forces suffered 70,000 deaths from the battle and the illnesses. Gao Huan himself was physically and emotionally drained, and he became ill, and he was forced to withdraw. Western Wei subsequently declared that Wei had killed Gao Huan with a powerful crossbow, and Gao Huan, in order to dispel the rumor, appeared before his army to sing the "Song of the
Chile" with
Hulü Jin in front of his generals. As he did, he wept bitterly. Gao's illness continued to progress once he returned to Jinyang, and he recalled Gao Cheng to Jinyang to give him final instructions. Gao Cheng became increasingly concerned that the powerful Chinese general
Hou Jing, who was then defending Luoyang and in charge of the provinces south of the Yellow River, would rebel, particularly after Hou refused a recall order. Gao Huan left Gao Cheng instructions not to announce his death, gave a list of ethnic Xianbei, Xiongnu and
Chile generals that he could depend on such as
Shedi Gan and
Hulü Jin, and orders to put
Murong Shaozong -- a capable general that Gao Huan had intentionally not promoted in order to allow Gao Cheng to do so—in charge of an army against Hou. He died in spring 547, and while a false casket was buried publicly, he was buried at a secret location in Cheng'an (成安, in modern
Handan,
Hebei). ==Family==