Empress Jia and and her clan remain in power until 300, when she deposes and assassinates the heir to the throne, Sima Yu, her husband's son by the concubine Consort Xie Jiu.

Sima Lun, who commands the imperial guards, takes this opportunity to kill the Empress Jia and her faction.

Sima Lun places himself in power and tries to centralize control over the powerful princes; this results in the rebellion of Sima Yun, who marches his troops to the capital against Sima Lun; Sima Yun is killed by Sima Lun's troops in the ensuing battle in Luoyang.

Sima Lun then imprisons Emperor Hui and styles himself as the new emperor.

 Emperor Hui’s regent Sima Jiong, the fourth of the eight princes commonly associated with the War of the Eight Princes, responds to Sima Yun’s usurpation by leading a coalition of forces, including Sima Ying and Sima Yong, against Sima Lun.

In 301, they defeat Sima Lun's troops, kill him, and then reestablish Emperor Hui as the emperor, with Sima Jiong exerting the most influence at the imperial court.

Sima Jiong tries to centralize power in his hands but the princes rebel against him: he is defeated by Sima Ai, the Prince of Changsha, and killed in 302.

Sima Ai, the fifth of the eight princes, becomes the effective regent, but in order to reduce opposition, he submits all important matters to Sima Ying, still stationed at Yecheng.