Huo Guang
Emperor Xuan's first wife, Empress Xu Pingjun was poisoned in 71 BC by the ambitious Xian (顯), the wife of the regent Huo Guang, who wanted to make her daughter Huo Chengjun empress; an objective that she was successful in after Empress Xu's death. While Huo Chengjun was empress, she allegedly tried unsuccessfully several times to poison Empress Xu's son Crown Prince Liu Shi, to make her potential future son the imperial heir.