Wu Zetian deposed her son Emperor Ruizong and proclaimed herself huangdi, establishing the Zhou dynasty with its capital at Luoyang, which she renamed Shendu. Having risen from concubine to empress consort under Emperor Gaozong, she had wielded effective power since his death in 683. Her fifteen-year reign saw expanded civil service examinations, patronage of Buddhism, and military campaigns against Tibet and the Western Turks. She abdicated in 705, and the Tang dynasty was restored under her son Emperor Zhongzong.