Princess Taiping
As of 690, Empress Wu was serving as empress dowager and regent over her son Emperor Ruizong, and Wu Youji was serving as a military officer. Empress Dowager Wu's only daughter Princess Taiping had been widowed since 688, when her husband Xue Shao (薛紹) was executed for participating in the rebellion of her cousin Li Chong, the Prince of Langye, against Empress Dowager Wu's authority. Empress Dowager Wu wanted to marry Princess Taiping to Wu Youji, who was however already married. Empress Dowager Wu therefore secretly had Wu Youji's wife assassinated, and then married Princess Taiping to him.