His mother Consort Ding Lingguang (丁令光) also gave birth to Emperor Wu's firstborn son and crown prince Xiao Tong, and therefore carried a special status within his palace even though she was never empress.
Xiao Tong therefore allowed the monk to bury a few items intended to dissolve the ill fortune, such as wax ducks, at the position reserved for the oldest son.
He only stopped the investigation when he was advised to do so by the prime minister Xu Mian, executing only the Taoist monk who had suggested the burial of wax ducks.
Under Confucian rules of succession, his oldest son Xiao Huan (蕭歡) the Duke of Huarong was expected to succeed him as crown prince, and Emperor Wu summoned Xiao Huan back to the capital Jiankang in order to do so.
Instead, against popular opinion, he installed Xiao Gang, his then-surviving oldest son, as crown prince on 5 August 531.
The poets Yu Jianwu and Xu Chi's writing style influenced Xiao Gang greatly.
As Crown Prince and "Assistant Monarch," Xiao Gang carried out much decision-making duties in the imperial administration.
Xiao Yuanming was captured, while Hou fled and, surprising the Liang governor of Southern Yu Province (南豫州, modern central Anhui), Wei An (韋黯), seized the key city Shouyang (壽陽, in modern Lu'an, Anhui), the capital of Southern Yu Province.
Instead of punishing Hou, however, Emperor Wu allowed him to serve as the governor of Southern Yu Province.
Soon, however, Hou, believing that Emperor Wu, who engaged in peace talks with Eastern Wei and appeared to be willing to betray him to exchange for Xiao Yuanming, rebelled in summer 548.
Eastern Wei (and its successor state Northern Qi, established in 550 as Gao Cheng's brother Gao Yang seized the throne from Emperor Xiaojing) largely seized the Liang provinces north of the Yangtze.
However, Hou still kept the emperor under heavy guard, and only several officials, including his cousin Xiao Zi (蕭諮) the Marquess of Wulin, Wang Ke (王克), and Yin Buhai were allowed to see him.
Ren first defeated and captured Emperor Jianwen's son Xiao Daxin (蕭大心) the Prince of Xunyang and governor of Jiang Province (江州, modern central and northern Jiangxi), and then continued on to try to attack Xiao Yi's territory.
In fear, Wang Ke and Yin stopped seeing the emperor, but Xiao Zi continued.
Ren was captured, and two other key generals, Song Zixian (宋子仙) and Ding He (丁和) were killed.
Hou had all of Emperor Jianwen's sons who were under his control, including Xiao Daqi the Crown Prince, executed.
(He soon regretted these actions, and considered restoring Emperor Jianwen to the throne and making Xiao Dong crown prince, but Wang persuaded him not to do so.)
In 552, after Wang Sengbian captured Jiankang, he had Emperor Jianwen's casket placed in the palace and then buried with imperial honors on 5 June.