In March of the sixth year of the Tang Dynasty, Tang Wuzong took Dan medicine, which caused an illness and could not afford to fall ill. Because Emperor Wuzong of Tang was unable to ascend to the throne for a long time and did not appoint a crown prince, it caused a shock to the government and the opposition. However, on March 21, a holy decree came from the palace, and Tang Wuzong actually made his uncle the emperor's uncle! Emperor Wuzong obviously had a son, so why did he pass the throne to his uncle?
In ancient China, the normal succession system for the throne has always been based on "fathers die and sons succeed", supplemented by "brothers and brothers". If the emperor did not have sons, it would be possible to pass the throne to his younger brother. However, Emperor Wuzong of Tang had sons, and there were five of them, "the fifth son of Emperor Wuzong, King Jun of Qi, who was crowned with five years of feng, Yi wang da, Yan Wang Qi, De Wang Yi, and Chang Wang Feng".
So why did Tang Wuzong let his son not stand, but set up his own uncle? The edict reads, "Crown Prince Chong is young, and must choose Xiande, and King Yi of Guang can be made the Emperor's uncle, change his name, and respond to the military and state affairs." The so-called "rushing young" refers to young age. Tang Wuzong was only 32 years old when he died, and his five sons were indeed not very old.
But is "The Crown Prince Rushing Young" the real reason? If it is only because the prince "rushes to childhood", he can still establish an imperial nephew, or adopt his nephew as a prince. In the history of the Tang Dynasty, there was a precedent for emperors to adopt nephews and establish themselves as princes. Emperor Wuzong's brothers Tang Jingzong and Tang Wenzong all had relatively older princes alive.
However, Tang Wuzong chose neither his son nor his nephew, but his thirteenth uncle! Tang Wuzong's thirteenth uncle, whose original name was Li Yi, was the son of Tang Xianzong, and although his rank was very high, he was actually only four years older than Emperor Wuzong. The edict said that Li Yi was "virtuous", but in fact Tang Wuzong looked down on him very much, "he was heroic and heroic, especially disrespectful".
How could Tang Wuzong set up someone he despised as his heir? There must be something wrong behind this! Looking at the historical data, we found that the problem was a group of eunuchs, the leader of whom was named Ma Yuanzhen! At that time, this person was a lieutenant in the Tang Dynasty's Shen ce army, holding the power of the forbidden army in the court, and it was he who issued the edict in the name of Emperor Wuzong.
Why did Ma Yuanzhen do this? It turned out that during the reign of Emperor Wuzong of Tang, Li Deyu was appointed to the throne, and the monarchs and courtiers cooperated closely to achieve "Huichang Zhongxing", and also dealt a blow to the power of eunuchs. At this time, Tang Wuzong was seriously ill, and Ma Yuanzhen saw the opportunity, and he wanted to improve his position in the court by supporting the merits.
At that time, Tang Wuzong's condition was very serious, and he had not been in the court since the thirteenth day of the first month. Ma Yuanzhen and others first cut off the emperor's contact with the prime ministers, "the prime minister please see, not allowed." Tang Wuzong, who was wise and divine, could no longer speak, "Ten Days could not speak", but his consciousness should still be sober, how much he hoped to see Li Deyu and order the aftermath.
However, due to the eunuchs' control of the court, the courtiers led by Li Deyu could not enter the palace at all. It was not until March 21 that Ma Yuanzhen and others corrected the edict, declaring Li Yi the Prince of Liguang the Emperor's uncle and letting him handle the affairs of the military state. Three days later, news came out of the palace that Emperor Wuzong of Tang had died, and the emperor's uncle Li Chen (who had changed his name) "was the throne before the coffin", that is, Tang Xuanzong.
On the first day of Tang Xuanzong's ascension to the throne, he issued a decree to drive the chancellor Li Deyu out of the imperial court and demote him to a magistrate. During the reign of Tang Xuanzong, although he also had some achievements, he failed to achieve greater achievements due to his expulsion of Li Deyu. Emperor Wuzong of Tang and Li Deyu "could not determine the heirs, and the eunuchs were in charge of the eunuchs" because the eunuchs held the military power of the forbidden army.
References: 1. Old Book of Tang; 2. New Book of Tang; 3. Zizhi Tongjian