Wu Zetian (624 – December 16, 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 consort and empress dowager and later, officially as empress regnant (皇帝) during the brief Zhou dynasty (周, 684-705), which interrupted the Tang dynasty (618–690 & 705–907).