Wu Chengsi
Emperor Gaozong died in 683, and was initially succeeded by his and Empress Wu's son Li Zhe the Crown Prince (as Emperor Zhongzong), but Empress Wu retained power as empress dowager and regent. In spring 684, after Emperor Zhongzong showed signs of independence, she deposed him and replaced him with another son, Li Dan the Prince of Yu, but wielded power even more tightly thereafter. Sometime during her regency, Wu Sansi became minister of defense (夏官尚書, "Xiaguan Shangshu"). Both he and his cousin Wu Chengsi (Wu Yuanshuang's son) advised Empress Dowager Wu to find excuses to kill two senior members of the imperial Li clan—Emperor Gaozong's uncles Li Yuanjia (李元嘉) the Prince of Han and Li Lingkui (李靈夔) the Prince of Lu due to their senior status. (Eventually, after two other princes—Emperor Gaozong's brother Li Zhen the Prince of Yue and Li Zhen's son Li Chong the Prince of Langye unsuccessfully rose against Empress Dowager Wu in 688, Empress Dowager Wu took the opportunity to also force Li Yuanjia and Li Lingkui, as well as many other members of the Li clan, to commit suicide or to execute them.) Wu Sansi and Wu Chengsi were also said to be often advocating that Empress Dowager Wu take over the throne herself as "emperor."