In February 684, Li Dan's mother Empress Wu demoted his older brother who had attempted to rule free of his mother, and named him emperor . Emperor Ruizong, however, was under control of his mother and did not have any real power. In October 690 he ceded the imperial throne to his mother, who installed herself as "emperor" -- the only woman in Chinese history ever to rule as emperor. Emperor Ruizong was reduced to the position of crown prince, with the unconventional title of ''Huangsi'' . In the following years, Empress Wu's nephews Wu Chengsi and Wu Sansi tried to have one of them named heir to the throne, but Wu Zetian resisted these calls. Eventually, in October 698, faced with foreign invasion and dissatisfaction at home, Empress Wu accepted the suggestion of the Di Renjie and recalled the exiled Li Xian to the capital Luoyang. Soon, Li Dan offered to yield the position of crown prince to his brother, and Li Xian became crown prince instead.
In 705, a coup overthrew Wu Zetian and restored Emperor Zhongzong to the throne. The five years of Emperor Zhongzong's reign were dominated by Zhongzong's empress consort, . In the beginning of July 710, Emperor Zhongzong died, allegedly poisoned by Empress Wei who then named Zhongzong's youngest son the Prince of Wen emperor . A mere two weeks later, Li Dan's sister Princess Taiping and Li Dan's son the Prince of Linzi launched a coup which resulted in the death of Empress Wei. Princess Taiping, Li Longji, and Li Longji's brother Li Chengqi the Prince of Song then persuaded Li Dan to take the throne himself, and he agreed, returning the throne in Emperor Shang's stead. Li Longji, although not the oldest son, was made crown prince on account of his accomplishments.
Soon, however, tensions between Princess Taiping, who had many supporters, and Li Longji mounted. Eventually, in September 712, Emperor Ruizong, believing that astrological signs called for a change of emperors, abdicated in favor of Li Longji . However, at Princess Taiping's suggestion, Emperor Ruizong, now carrying the title of ''Taishang Huang'' , continued to wield actual power. However, in 713, suspecting Princess Taiping of planning a coup, Emperor Xuanzong acted first, killing her associates and forcing her to commit suicide. After the death of Princess Taiping, Emperor Ruizong himself yielded imperial powers to Emperor Xuanzong and left the governmental scene. He died in 716.
Li Xulun was born in 662, as the youngest son of and his second wife . Later that year, he was created the Prince of Yin. In 664, he was nominally made the commandant at Ji Prefecture and the Chanyu Protectorate General . It was said that, as he grew, he became known for humility, the love for his siblings, and talent in . In 666, his title was changed to Prince of Yu. In 669, his title was changed to Prince of Ji, and his name was changed from Xulun to Lun. In 675, his title was changed to Prince of Xiang. In 678, his title was changed back to Prince of Yu, and his name was further changed to Li Dan. He was also made the prefect of Luo Prefecture , the prefecture containing the eastern capital Luoyang. Sometime between 676 and 679, he married his wife .
Emperor Gaozong died in 683 and was succeeded by Li Dan's older brother the Crown Prince , but Empress Wu retained power as empress dowager and regent. In 684, when Emperor Zhongzong displayed signs of independence, she deposed him and replaced him with Li Dan , but wielded power even more firmly. Indeed, she housed Emperor Ruizong in a different palace and did not let him meet the imperial officials or give input on affairs of state. Emperor Ruizong's wife Princess Liu was created empress, while her son Li Chengqi was created crown prince.
Soon after Emperor Ruizong took the throne, Empress Dowager Wu carried out a major renaming of governmental offices and banners. She, who disliked the capital Chang'an, also elevated Luoyang's status, making it a co-equal capital with Chang'an. She further, at the suggestion of her nephew Wu Chengsi, built an ancestral temple for five generations of her ancestors and had Emperor Ruizong posthumously create them princes.
In fall 684, Li Jingye the Duke of Ying , started a rebellion against Empress Dowager Wu at Yang Prefecture, seeking the restoration of Emperor Zhongzong. Empress Dowager Wu, in response, sent the general Li Xiaoyi , assisted by the generals Li Zhishi and Ma Jingchen to suppress Li Jianye's rebellion, and Li Xiaoyi quickly did so. Meanwhile, believing the Pei Yan to be undermining her authority, she executed Pei under accusation of treason and demoted a large number of officials and generals who dared to speak in Pei's defense, later executing some of them.
In 686, Empress Dowager created a number of bronze boxes designed to encourage secret reports of crimes. She also began to retain a group of secret police officials to carry out torture and interrogation of people suspected of opposing her rule, including Suo Yuanli, , and Lai Junchen. On one occasion, she offered to return imperial authorities to Emperor Ruizong, but Emperor Ruizong knew that she was not actually intending to do so, and therefore declined. She thereafter resumed exercising imperial powers.
Emperor Ruizong had largely stayed out of political matters during these years, but he made an exception in 687, when Empress Dowager Wu believed the chancellor Liu Yizhi, who had previously served on his staff when he was a prince, whom she had trusted and promoted, to have turned against her in favoring that she return imperial authorities to Emperor Ruizong. She had Liu accused of corruption and arrested, and Emperor Ruizong personally wrote a petition to request her to spare Liu -- which, however, as Liu observed, had the opposite effect, and she ordered Liu to commit suicide.
In 688, fearing that Empress Dowager Wu was using a ceremony to worship the god of the Luo River as an excuse to summon them to Luoyang to slaughter them, the imperial princes considered rebellion, and one was launched by Emperor Ruizong's uncle the Prince of Yue and Li Zhen's son the Prince of Langye, claiming that Emperor Ruizong was under arrest and needed to be rescued. However, both Li Zhen and Li Chong were quickly defeated; Li Chong was killed in battle, while Li Zhen committed suicide. Empress Dowager Wu used this opportunity to carry out a major purge of senior imperial Li clan members, including Emperor Ruizong's granduncles Li Yuanjia the Prince of Han and Li Lingkui the Prince of Lu.
In 690, Empress Dowager Wu received a number of petitions that she take the throne herself, and Emperor Ruizong also submitted such a petition. She accepted, and she took the throne as "emperor," establishing a new Zhou Dynasty and interrupting Tang Dynasty. She demoted Emperor Ruizong to the position of crown prince , and changed his name back to Lun. She further had him take her family name of Wu.
During Wu Zetian's reign
Despite the fact that Wu Zetian created Li Dan crown prince, she considered creating one of her nephews, Wu Chengsi the Prince of Wei or Wu Sansi the Prince of Liang crown prince, and a petition drive for Wu Chengsi to be created crown prince reached its peak in 691. The chancellors Cen Changqian and Ge Fuyuan were even executed for opposing it, but Wu Zetian never did carry out the change, and when the leader of the petition drive, Wang Qingzhi was caned to death by the official Li Zhaode, the petition drive dissipated.
Meanwhile, in 693, Wu Zetian's lady in waiting Wei Tuan'er , who was resentful of Li Dan for reasons lost to history, falsely accused Li Dan's wife Crown Princess Liu and concubine Consort Dou of witchcraft, and Wu Zetian killed Crown Princess Liu and Consort Dou. In fear of offending Wu Zetian, Li Dan did not dare to mourn either and continued to behave normally. When Wei Tuan'er tried to further falsely accuse Li Dan, someone in turn reported her activities to Wu Zetian, and Wu Zetian executed her. Still, thereafter, Li Dan's sons were demoted in rank and kept under secure watch. Later in 693, the officials Pei Feigong and Fan Yunxian were executed on account of meeting Li Dan secretly, and there were accusations that Li Dan was planning to rebel against Wu Zetian. Wu Zetian ordered that the officials not be allowed to meet Li Dan, and further arrested his servants to interrogate them. The secret police official Lai Junchen tortured Li Dan's servants, and many of them, unable to stand up to the torture, considered falsely implicating Li Dan. One of them, An Jinzang , however, cut his own belly open and proclaimed Li Dan's innocence. When Wu Zetian heard this, she sent imperial doctors to save An, and, impressed by An's willingness to die to show Li Dan's innocence, ended the investigation against Li Dan.
In 698, after Wu Zetian had, at the encouragement of the chancellors Di Renjie, Wang Fangqing, and Wang Jishan, as well as her close associate Ji Xu and lovers Zhang Yizhi and Zhang Changzong, recalled Li Zhe from exile, Li Dan offered to yield the crown prince position to Li Zhe. Wu Zetian agreed, and created Li Zhe crown prince and Li Dan the Prince of Xiang.
In 699, Wu Zetian, in fear that after her death that Li Xian and the Wu clan princes would not be able to coexist peacefully, had Li Xian, Li Dan, their sister Princess Taiping, her husband Wu Youji , and the other Wu clan princes swear an oath to each other and read the oaths to the gods. The oaths were then carved on iron and kept in the imperial archives. Later that year, the restrictions on his and Li Xian's sons were lifted, and they were allowed to live outside the palace.
In 701, when there was an incursion by the Eastern Tujue khan Ashina Mochuo, Li Dan was put in command of an army to defend against the attack, but before the army could be launched, Ashina Mochuo withdrew. Subsequently, Li Dan was nominally put in charge of the imperial guards.
In 702, Wu Zetian put Li Dan in command of an army and made the prefect of Bing Prefecture , with Wu Sansi, Wu Youning, and Wei Yuanzhong as his assistants, apparently preparing to attack Eastern Tujue, but the army was never launched. Later that year, she had Li Xian, Li Dan, and Princess Taiping submit formal petitions to have Zhang Changzong created a prince. She then formally rejected the petitions, but created Zhang Changzong and Zhang Yizhi dukes.
In 703, Li Dan was made the prefect of Yong Prefecture , the prefecture that included Chang'an.
During Emperor Zhongzong's second reign
In 705, Wu Zetian was overthrown in a coup led by Zhang Jianzhi, Cui Xuanwei, Huan Yanfan, Jing Hui, and Yuan Shuji. Li Xian was restored to the throne, and he gave Li Dan the special title of ''Anguo Xiangwang'' , literally "the Prince of Xiang who pacified the the state." Emperor Zhongzong also gave Li Dan the title of ''Taiwei'' and made him a chancellor with the designation of ''Tong Zhongshu Menxia Sanpin'' . Li Dan declined both honors, and Emperor Zhongzong then offered to create him crown prince, which Li Dan declined as well. Emperor Zhongzong subsequently created his son Li Chongjun crown prince.
In 707, Li Chongjun, who was not born of Emperor Zhongzong's powerful wife , was angry that Empress Wei's daughter Li Guo'er the Princess Anle and her husband Wu Chongxun repeatedly insulted him and were trying to persuade Emperor Zhongzong to create Li Guo'er crown princess to displace Li Chongjun, rose in rebellion and killed Wu Sansi and Wu Chongxun. His subsequent attack on the palace, however, was repelled, and he was killed in flight. Some of his followers implicated LI Dan and Princess Taiping after they were arrested and interrogated. Emperor Zhongzong initially had the imperial censor Xiao Zhizhong put in charge of investigating Li Dan and Princess Taiping, but at Xiao's earnest urging stopped the investigation.
In 708, when Li Guo'er married again, to Wu Yanxiu , Li Dan was the ceremonial protector of her litter.
During Emperor Shang's reign
On July 3, 710, Emperor Zhongzong died suddenly -- a death that traditional historians believed to be a poisoning carried out by Empress Wei and Li Guo'er, so that Empress Wei could be Empress Regnant like Wu Zetian and Li Guo'er could be crown princess. Under a will drafted for Emperor Zhongzong by Princess Taiping and Emperor Zhongzong's concubine , Emperor Zhongzong's son by another concubine, would be named emperor, with Empress Wei serving as empress dowager and regent, but with Li Dan as co-regent. This plan, however, was opposed by and ultimately altered at the suggestions of Empress Wei's cousin Wei Wen and Zong Chuke. After Li Chongmao took the throne , Empress Wei became empress dowager and regent, while Li Dan only received an entirely ceremonial title of senior advisor to the crown prince -- as there was no crown prince at the time.
Meanwhile, Empress Dowager Wei's party viewed Li Dan and Princess Taiping as threats and considered eliminating them. One of her partisans, Cui Riyong, was fearful of what would happen if the plan failed, and therefore informed the plan to Li Dan's son the Prince of Linzi. Li Longji responded by conspiring with Princess Taiping, Princess Taiping's son Xue Chongjian , as well as several low level officials close to him -- Zhong Shaojing, Wang Chongye , Liu Youqiu, and Ma Sizong -- to act first. Meanwhile, Empress Wei's nephews Wei Bo and Gao Song , who had recently been put in command of imperial guards and who had tried to establish their authority by dealing with the guards harshly, had alienated the guards, and the guard officers Ge Fushun , Chen Xuanli , and Li Xianfu thereafter also joined the plot.
Without first informing Li Dan, the conspirators rose on July 21, first killing Wei Bo, Gao, and Empress Wei's cousin Wei Gui . They then attacked the palace. When Empress Dowager Wei panicked and fled to an imperial guard camp, a guard beheaded her. Li Guo'er, Wu Yanxiu, and the powerful lady in waiting Lady Helou were killed as well. Li Longji soon slaughtered a number of officials in Empress Dowager's faction as well as her clan, while displaying Empress Dowager Wei's body on the street. Li Dan took over as regent, but at the urging of Princess Taiping, Li Longji, and Li Chengqi, Li Dan soon took the throne from Emperor Shang and again became emperor. Emperor Shang was reduced in rank back to Prince of Wen.
Emperor Ruizong was immediately faced with the issue of whom to make crown prince -- as Li Chengqi, as the oldest son overall and the oldest son of his wife, was the appropriate heir under Confucian principles of succession, but Li Longji had been the one whose accomplishments had allowed him to retake the throne. He hesitated. Li Chengqi declined consideration to be crown prince -- stating to his father:
Li Chengqi wept and begged to yield for several days, and after further persuasion by the Liu Youqiu -- who had been part of Li Longji's coup plans -- Emperor Ruizong agreed, and created Li Longji crown prince. Li Longji submitted a petition offering to yield to Li Chengqi, but Emperor Ruizong rejected it.
Emperor Ruizong reversed many of Emperor Zhongzong's actions and posthumously honored many people who lost their lives during the reigns of Wu Zetian and Emperor Zhongzong. He further removed thousands of officials that Emperor Zhongzong had commissioned at the recommendations of powerful courtiers, without having been submitted for examination by the examination and legislative bureaus of government, as was proper. Meanwhile, though, with Emperor Ruizong considered meek, the court was dominated by two competing factions -- of Princess Taiping and Li Longji. Indeed, it was said that whenever chancellors brought proposals to Emperor Ruizong, Emperor Ruizong would ask them whether they had consulted Princess Taiping and Li Longji, and only act if the chancellors had consulted them. Princess Taiping, finding Li Longji to be not receptive to her influences, began to spread news of offenses by Li Longji, hoping that he would eventually be removed. In 711, the chancellors and Song Jing tried to defuse the situation by having Princess Taiping sent to Pu Prefecture and the two princes with arguable better claims on the throne than Li Longji -- Li Chengqi and Li Shouli the Prince of Bin -- out of the capital to serve as prefectural prefects, but after their plan was discovered by Princess Taiping, she angrily complained, and was recalled to the capital along with Li Chengqi and Li Shouli. Yao and Song, credited with reforming the civil service system, were demoted, and it was said that thereafter, the civil service system became as confused as it was during Emperor Zhongzong's reign.
In 712, the general Sun Quan , the commandant at You Prefecture , aggressively attacked the Xi chieftain Li Dabu , and was defeated by Li Dabu, at the loss of nearly the entire army.
Later in 712, Princess Taiping had astrologers warn Emperor Ruizong that the constellation that symbolized the imperial throne, ''Dizuo'' , showed that there would be a change in the emperor's position — believing that Emperor Ruizong would suspect Li Longji of plotting a coup and that she could remove Li Longji this way. Instead, Emperor Ruizong, reasoning that the change in the emperor's position could be accounted by an orderly transition, offered to pass the throne to Li Longji. Princess Taiping fervently opposed it, and Li Longji initially declined, but at Emperor Ruizong's insistence finally accepted and took the throne . However, at Princess Taiping's suggestion, Emperor Ruizong retained much of the imperial power as ''Taishang Huang'' , and his edicts continued to carry greater force than Emperor Xuanzong's.
As retired emperor
Meanwhile, Princess Taiping continued to be highly influential in governmental matters through Emperor Ruizong, and most chancellors were her associates. Liu Youqiu and the general Zhang Wei , with Emperor Xuanzong's approval, planned to mobilize the imperial guards to kill several of those chancellors -- Dou, Cui, and Cen However, after Zhang told the plan to the imperial censor Deng Guangbin , the news was leaked. Liu was arrested, and initially set to be executed. Emperor Xuanzong interceded on his behalf with Emperor Ruizong, and Liu, Zhang, and Deng were spared but exiled.
Later in 712, Emperor Ruizong decreed that Emperor Xuanzong lead a group of soldiers to examine the northern border. However, the group of conscripted soldiers was disbanded in spring 713, and the plan was never carried out.
By summer 713, it was said that Princess Taiping, Dou, Cen, Xiao, Cui; along with other officials Xue Ji, Li Jin the Prince of Xinxing , Li You , Jia Yingfu , Tang Jun ; the generals Chang Yuankai , Li Ci , and Li Qin ; and the monk Huifan, were plotting to overthrow Emperor Xuanzong. It was further said that they discussed, with the lady in waiting Lady Yuan to poison an aphrodisiac that Emperor Xuanzong took regularly known as ''chijian'' ). When this alleged plot was reported to Emperor Xuanzong by Wei Zhigu, Emperor Xuanzong, who had already received advice from Wang Ju , Zhang Shuo, and Cui Riyong to act first, did so. He convened a meeting with his brothers Li Fan the Prince of Qi, Li Ye the Prince of Xue, Guo Yuanzhen, along with a number of his associates — the general Wang Maozhong , the officials Jiang Jiao and Li Lingwen , his brother-in-law Wang Shouyi , the eunuch Gao Lishi, and the military officer Li Shoude — and decided to act first. On July 29, Emperor Xuanzong had Wang Maozhong take 300 soldiers to the imperial guard camp to behead Chang and Li Ci. Then, Jia, Li You, Xiao, and Cen were arrested and executed as well. Dou fled into a canyon and committed suicide by hanging. Xue Ji was forced to commit suicide. When Emperor Ruizong heard about this, he quickly ascended the tower at Chengtian Gate to ascertain what was happening. Guo reported to him Emperor Xuanzong's intentions, and Emperor Ruizong felt compelled to affirm Emperor Xuanzong's actions in an edict. The next day, Emperor Ruizong issued an edict transferring all authorities to Emperor Xuanzong and moved to a secondary palace, Baifu Hall . Meanwhile, Princess Taiping, hearing what happened to her associates, fled into a temple in the mountains, only appearing three days later. Emperor Xuanzong ordered her to commit suicide at home, and put to death her sons and associates, except for Xue Chongjian. It was said that when Emperor Ruizong was at Baifu Hall, the only person who attended to him regularly was Emperor Xuanzong's daughter Princess Shouchun.
In 716, Emperor Ruizong died at Baifu Hall. He was enshrined into the imperial temple, along with Emperor Xuanzong's mother Consort Dou, who was posthumously honored an empress. Emperor Xuanzong had his daughter Princess Wan'an become a Taoist nun to seek blessings for Emperor Ruizong.
* ''Wenming'' 684
* ''Guangzhai'' 684
* ''Chuigong'' 685-689
* ''Yongchang'' 689
* ''Zaichu'' 690
* ''Jingyun'' 710-712
* ''Taiji'' 712
* ''Yanhe'' 712
Chancellors during reign
* Liu Rengui
* Pei Yan
* Guo Daiju
* Cen Changqian
* Wei Xuantong
* Liu Jingxian
* Wei Hongmin
* Wang Dezhen
* Liu Yizhi
* Wu Chengsi
* Li Jingchen
* Qian Weidao
* Shen Junliang
* Cui Cha
* Wei Fangzhi
* Wei Siqian
* Pei Judao
* Su Liangsi
* Wei Daijia
* Zhang Guangfu
* Wang Benli
* Fan Lübing
* Xing Wenwei
* Wu Youning
* Wei Anshi
* Tang Xiujing
* Li Jiao
* Su Gui
* Zhang Renyuan
* Zhang Xi
* Pei Tan
* Cen Xi
* Liu Youqiu
* Zhong Shaojing
* Li Rizhi
* Xue Ji
* Wei Sili
* Xiao Zhizhong
* Zhao Yanzhao
* Cui Shi
* Cui Riyong
* Song Jing
* Li Chengqi
* Guo Yuanzhen
* Zhang Shuo
* Dou Huaizhen
* Lu Xiangxian
* Wei Zhigu
** Emperor Gaozong of Tang
** Wu Zetian
** , mother of Prince Xian and Princesses Shouchang and Dai
* Major Concubines
** Consort Dou , mother of Crown Prince Longji and Princesses Jinxian and Yuzhen, posthumously honored Empress Zhaochengshunsheng
** Consort Liu, mother of Prince Hui
** Consort Cui, mother of Prince Fan
** Consort Wang, mother of Prince Ye
** Consort Cui, mother of Princess Xi
** Li Xian , né Li Chengqi , initially the Prince of Yongping, later Crown Prince , later Imperial Grandson , later Prince of Shouchun , later Prince of Song , later Prince of Ning , posthumously honored Emperor Rang
** Li Hui , né Li Chengyi , initially the Prince of Heng , later the Prince of Hengyang , later the Prince of Shen , posthumously honored Crown Prince Huizhuang
** Li Longji , initially the Prince of Chu , later the Prince of Linzi , later the Prince of Ping , later Crown Prince , later Emperor Xuanzong of Tang
** Li Fan , né Li Longfan , initially the Prince of Zheng, later the Prince of Wei , later the Prince of Baling , later the Prince of Qi , posthumously honored Crown Prince Huiwen
** Li Ye , né Li Longye , initially the Prince of Zhao , later the Prince of Zhongshan , later the Prince of Pengcheng, later the Prince of Xue , posthumously honored Crown Prince Huixuan
** Li Longti , initially the Prince of Ru'nan, died early, posthumously honored the Prince of Sui
** Princess Shouchang
** Princess Zhaohuai of Anxing
** Princess Jingshan
** Princess Huaiyang
** Li Hua , the Princess Dai
** Princess Liang, courtesy name Huazhuang
** Princess Xue
** Princess Xi
** Princess Jinxian
** Princess Yuzhen, courtesy name Chiying
** Princess Huo