(Wu) Zhou dynasty in the context of "Emperor Ruizong of Tang"

Empress Zetian (624 – 16 December 705), commonly known as Wu Zetian, personal name Wu Zhao, was the empress regnant (huangdi, 皇帝) and only ruler of the (Wu) Zhou dynasty from 690 to 705. She had previously held power as the second wife and empress consort of Emperor Gaozong of the Tang dynasty from 660 to 683 and as empress dowager during the reigns of her sons Emperors Zhongzong and Ruizong of Tang between 683 and 690, holding de facto power during these periods. She was the only female sovereign in the history of China who is widely regarded as legitimate. Modern scholarship has re-examined Wu Zetian's rule beyond traditional portrayals of manipulation and cruelty. Recent studies highlight her administrative reforms, expansions of the civil-service examination system, and support of Buddhist symbolism as instruments of governance and legitimacy. During her 45 year tenure, China grew larger, its culture and economy were revitalized, and corruption in the court was reduced. She was eventually removed from power during the Shenlong Coup [zh] and died a few months later.

In early life, Empress Wu was a concubine of Emperor Taizong. After his death, she married his ninth son and successor, Emperor Gaozong, officially becoming Gaozong's empress, the highest-ranking of his consorts, in 655. Empress Wu held considerable political power even before becoming empress, and began to control the court after her appointment. After Gaozong's debilitating stroke in 660, she became administrator of the court, a position with similar authority to the emperor's, until 683. History records that she "was at the helm of the country for long years, her power no different from that of the emperor". On Emperor Gaozong's death in 683, rather than entering retirement, and not interfering in the government, Empress Wu broke with tradition and took acquisition of complete power, refusing to allow either of her sons to rule. She took the throne in 690 by officially changing the name of the dynasty from Tang to Zhou, changing the name of the imperial family from Li to Wu, and holding a formal ceremony to crown herself as emperor.