Sima Yu's father Sima Zhong was developmentally disabled, and before he, then crown prince, was to marry his wife Jia Nanfeng, Zhong's father Emperor Wu gave him one of his own concubines, Consort Xie Jiu (謝玖), so that Consort Xie could teach him how to have sexual relations.
Emperor Wu was surprised by this perceptive observation by a child, and praised the young prince as very much like his own grandfather Sima Yi.
[9] As Crown Prince Yu grew in age, however, he lost some of the good reputation that he had as a child, as he disliked studying and spent much time on building projects and games.
When Crown Prince Yu was in the palace to make an official petition to have his ill son Sima Bin (司馬彬) created a prince, Empress Jia forced him to drink a large amount of wine and, once he was drunk, had him write out a statement in which he declared intention to murder the emperor and the empress and to take over as emperor.
Empress Jia presented the writing to the officials and initially wanted Crown Prince Yu executed—but after some resistance, she only had him deposed and reduced to status of a commoner on 6 February.
Wang Yan divorced his daughter from the crown prince, who wrote an extant, lengthy letter to her explaining the incident through which Empress Jia framed him.