Empress Cao (曹皇后, personal name unknown) was the wife of Dou Jiande, an agrarian rebel leader who claimed the title of Prince of Xia at the end of the Chinese dynasty Sui Dynasty. Nothing is known about her personal background. She was said to be frugal in her living, as even after Dou conquered modern Hebei and had substantial holdings, she had no decoration on her clothing, and only had less than 10 maids attending her. After Dou defeated and killed Yuwen Huaji, who carried a large number of ladies in waiting of Emperor Yang of Sui in his possession, Dou disbanded the ladies in waiting. (Novels fictionalizing the era generally attribute Dou's disbanding of the ladies in waiting to his love for her and her jealousy, but nothing is recorded in history suggesting that she was, in fact, jeal