Wu Zetian (February17, 624December16, 705), also known as Wu Zhao, Wu Hou, and during the later Tang dynasty as Tian Hou, referred to in English as Empress Consort Wu or by the deprecated term "Empress Wu", was a Chinese sovereign who ruled unofficially as Empress and later, officially as Emperor of China (皇帝) during the brief Zhou dynasty (周, 684-705), which interrupted the Tang dynasty (618–690 & 705–907). Wu was the only female emperor of China in more than four millennia.