Pei Yan
Soon, Empress Wu's relationship with Li Xián also deteriorated because Li Xián had become unsettled after hearing rumors that he was not born to Empress Wu—but to her sister, the Lady of Han. When Empress Wu heard of his fearfulness, she became angry with him. Furthermore, the sorcerer Ming Chongyan (), whom both she and Emperor Gaozong respected, had stated that Li Xián was unsuitable to inherit the throne and was assassinated in 679. The assassins were not caught—causing Wu to suspect that Li Xián was behind the assassination. In 680, Li Xián was accused of crimes and during an investigation by the officials Xue Yuanchao, Pei Yan, and Gao Zhizhou, a large number of weaponry was found in Li Xián's palace. Empress Wu formally accused Li Xián of treason and the assassination of Ming. Li Xián was deposed and exiled.