There are also many who have been emperor twice.
Let's list them all by dynasty (only the great unification dynasty)
The first is the Western Jin Dynasty. There was an emperor of the Western Jin Dynasty who was twice emperor, that is, Sima Zheng, the emperor of Jinhui, yes, the idiot emperor who said" "Why don't you eat meat when you don't have food?". In the first year of Yongkang (300), Sima Lun, the King of Zhao, used a divisive tactic, first designing that the crown prince Sima Suo be killed by Empress Jia Nanfeng, and then in the name of avenging the crown prince, he instigated the old department of the crown prince Sima Suo and sima Ran, the king of Qi, to raise an army against Jia, and then successfully entered Luoyang and killed Jia Nanfeng. After that, Sima Lunquan fell to the opposition, leading the military forces of Zhongzhong, Xiangguo, and Dudu, adding Jiuxi, and soon forcing Emperor Hui of Jin to abdicate and establish himself as emperor, with the era name being established. In the same year, Sima Ran the Prince of Qi, Sima Yuan, the King of Hejian, and Sima Ying the King of Chengdu rebelled, but Sima Lun was defeated and had to announce his abdication and return to Emperor Hui of Jin, so that Emperor Hui of Jin, who had just been deposed for less than a few months, became emperor again.
Then there is the Tang Dynasty. There were three emperors of the Tang Dynasty who were emperors twice, one was Li Xian, one was Emperor Ruizong of Tang, and the other was Li Ye of Tang Zhaozong. First of all, when Li Xian and Li Dan were emperors twice, li xian of Tang Zhongzong was emperor first, and then Li Dan of Tang Ruizong was emperor again, and they were deposed because of their mother, Wu Zetian, the only female emperor in China. Emperor Zhongzong of Tang deposed Li Xian, mainly because he reused Wei's foreign relatives in an attempt to divide Wu Zetian's power, so Wu Zetian learned of it and deposed him. And Tang Ruizong Li Dan would be deposed, because Wu Zetian wanted to be emperor himself, so Li Dan, the emperor, was naturally deposed by him.
Subsequently, Wu Zetian established Wu Zhou and ruled the world for fifteen years. Until the outbreak of the Shenlong Coup in 705, Wu Zetian abdicated, Wu Zhou Fang perished, and the Tang Dynasty was restored. In the same year, with the support of Zhang Kamzhi and others, Emperor Zhongzong of Tang announced that Li Xian had been reinstated and changed his era name to Jinglong. In June of the fourth year of Jinglong (710), Emperor Zhongzong of Tang, Li Xian, was poisoned by Empress Wei and Princess Anle in collusion. In the same year, Li Longji, the king of Linzi, joined forces with his aunt Princess Taiping and formed a "Tanglong coup" with the forbidden generals Ge Fushun and Chen Xuanli to kill Empress Wei and Princess Anle and proclaim Li Dan as emperor for Tang Ruizong.
Secondly, Tang Zhaozong Li Ye. In November of the third year of Gwanghwa (900), Emperor Zhaozong Li Ye was imprisoned by eunuchs led by lieutenant Liu Jishu, and his throne was succeeded by the crown prince. The following year, with the help of Zhu Wen, Emperor Zhaozong was reinstated, and lieutenant Liu Jishu and other rebels were killed.
The second was the Song Dynasty. There was one emperor of the Song Dynasty who was twice emperor, that is, Emperor Gaozong of Song, who wrongfully killed Yue Fei. In the third year of Jianyan (1129), Miao Fu and Liu Zhengyan launched the Miao-Liu Mutiny, and Emperor Gaozong was forced to abdicate, and his son Zhao Xu was made emperor. In the same year, the chancellor Zhang Jun led the army to quell the rebellion, Miao Fu and Liu Zhengyan failed in a coup, Emperor Gaozong was restored to the throne, the capital was moved to Lin'an Province, and the era name was changed back to Jianyan.
Then there is the Yuan Dynasty. There was one emperor of the Song Dynasty who was twice emperor, that is, Emperor Wenzong of Yuanwen's son, Jin Tu Timu'er. In the second year of the Celestial Calendar (1329), under political pressure, Emperor Wenzong of Yuan was forced to abide by the promise made at that time that year that he would "honor the eldest brother to the end of the year, in order to fulfill the heart of the older brother", and gave way to his elder brother Bao'er Only Jin and Shi Ju, in order to be Emperor Yuanmingzong. In the same year, less than a few months after giving way, with the sudden death of Emperor Mingzong of Yuan, with the support of Yan Timur, Emperor Wenzong of Yuan was restored to the throne again as emperor.
Finally, there was the Ming Dynasty. There was one emperor of the Ming Dynasty who was twice emperor, that is, Emperor Ming Yingzong Zhu Qizhen. In the fourteenth year of orthodoxy (1449), Zhu Qizhen personally conquered Wala, but was defeated by Tumu Fort, and he himself was captured by Wala. Later, Wala wanted to borrow Zhu Qizhen and threaten the Ming court to cede territory, and in order to avoid being threatened by Wala, under the leadership of Yu Qian, the Ming court supported Zhu Qiyu as emperor for the Ming Dynasty. In the eighth year of Jingtai (1457), the rebellion of the gate broke out, and Zhu Qizhen was once again supported by the eunuch Cao Jixiang, the governor Zhang Xuan, the left capital of the Capital, Yang Shan, the capital of the Imperial Household, and Xu Bin, the secretary of the TaichangQing.
In addition, in the long history of China for more than 2,000 years, there has also been a more powerful emperor, that is, Puyi, the xuantong emperor who has been emperor for three times. Puyi was emperor from 1908 to 1912, from July 1, 1917 to July 12, 1917, and from 1934 to 1945. Of course, in these three imperial careers, Puyi is a puppet emperor, compared to the emperors who have been emperors twice mentioned above, Puyi has no real power, just the name of an emperor, just a puppet emperor.