Emperor Wu has resolved by 290 to let Yang Jun and Sima Liang both be regents, but after he writes his will, the will is seized by Yang Jun, who instead has another will promulgated in which Yang alone is named regent.

Emperor Wu dies soon hereafter, and Crown Prince Zhong ascends the throne as Emperor Hui.

Empress Yang is honored as empress dowager, Crown Princess Jia becomes empress, and Prince Yu becomes crown prince.

Although the Jin dynasty has provided a brief period of unity after conquering the Kingdom of Wu, the longest-lived of the Three Kingdoms competing for control of China after the fall of the Han Dynasty, in 280, a complex power struggle begins among the Sima clan following the death of Emperor Wu in 290.

The new emperor is developmentally disabled, and factions fight to control the imperial court.

Initially, the emperor's stepmother, Empress Dowager Yang, exerts the most power at the courts, and empowers her family, the Yang consort clan, with her father Yang Jun given the most power.

Yang Jun quickly shows himself to be autocratic and incompetent, drawing the ire of many other nobles and officials.

He tries to appease them by making many bestowments of titles and honors among them, but this only brings further contempt for his actions.

Knowing Empress Jia to be strong-willed and treacherous, he tries to place people loyal to him in charge of all the defense forces of the capital, Luoyang, and orders that all edicts not only be signed by the emperor but also by Empress Dowager Yang before they could be promulgated.

Empress Jia, however, wants to be involved in the government, and is angry that she is constantly rebuffed by Empress Dowager Yang and Yang Jun.

She therefore conspires with the eunuch Dong Meng and the generals Meng Guan and Li Zhao against the Yangs.

She tries to include Sima Liang into the conspiracy, but Sima Liang declines; instead, she persuades her brother-in-law, Sima Wei the Prince of Chu, to join her plan.

Sima Wei is the fifth son of Emperor Wu by his concubine Consort Shen.