武承嗣
In 697, Wu Chengsi became aware that the official Qiao Zhizhi (喬知之) had a beautiful concubine named Biyu (碧玉) -- whom Qiao loved so much that he declined to formally marry a wife. Wu Chengsi invited Biyu to come to his mansion to teach his own concubine arts, and then kept her and would not allow her to go back to Qiao. Qiao wrote a poem entitled "the Mourning of Lüzhu" (綠珠怨) and sent it to Biyu. When Biyu read it, she was so distressed that she committed suicide by jumping into a well. When Wu Chengsi found this poem on her, he had secret police officials falsely accuse Qiao of crimes, and Qiao was killed. Later that year, Wu Chengsi was again made chancellor, but less than a month later, he was again removed.