Wu Zetian (Simplified Chinese: 武则天; Traditional Chinese: 武則天; pinyin: Wǔ Zétiān) (625 – December 16, 705), personal name Wu Zhao (武曌), was the only woman in the history of China to assume the title of Emperor. Ruling China first through puppet emperors from 665 to 690, not unprecedented in Chinese history, she then broke all precedents when she founded her own dynasty in 690, the Zhou (周) (interrupting the Tang Dynasty), and ruled personally under the name Emperor Shengshen (聖神皇帝) from 690 to 705. Her rise and reign has been criticized harshly by Confucian historians but has been viewed under a different light after the 1950s.

Road to power
After Emperor Gaozong started to suffer from strokes from November 660 on, she began to govern China from behind the scenes. She was even more in absolute control of power after she had Shangguan Yi (上官儀) executed and the demoted crown prince Li Zhong (李忠) forced to commit suicide in January 665, and henceforth she sat behind to the now silent emperor during court audiences (most probably, she sat behind a screen at the rear of the throne) and took decisions. She reigned in his name and then, after his death, in the name of subsequent puppet emperors (her son Emperor Zhongzong and then her younger son Emperor Ruizong), only assuming power herself in October 690, when she proclaimed the Zhou Dynasty, named after her father's nominal posthumous fief as well as in reference to the illustrious Zhou Dynasty of ancient Chinese history from which she claimed the Wu family was descended. In December 689, ten months before she officially ascended the throne, she had the government create the character Zhao (曌), an entirely new invention, created along with 11 other characters in order to show her absolute power, and she chose this new character as her given name, which became her taboo name when she ascended the throne ten months later. The character is made up of 2 pre-existing characters: "Ming" up top meaning "light" or "clearness"; and "kong" on the bottom meaning "sky". The idea behind this is the implication that she is like the light shining from the sky. Even the pronunciation of the new character is exactly the same as "shine" in Chinese. On ascending the throne, she proclaimed herself Emperor Shengshen, the first woman ever to use the title emperor (皇帝) which had been created 900 years before by the first emperor of China Qin Shi Huang. Indeed she was the only woman in the 2100 years of imperial China ever to ascend the Dragon Throne, and this again utterly shocked Confucian elites.
Traditional Chinese political theory (see the similar Salic law) did not allow a woman to ascend the throne, and Empress Wu was determined to quash the opposition and promote loyal officials within the bureaucracy. Her regime was characterized by Machiavellian cleverness and brutal despotism. During her reign, she formed her own Secret Police to deal with any opposition that might arise. She was also supported by her two lovers, the Zhang brothers (Zhang Yizhi, 張易之, and his younger brother Zhang Changzong 張昌宗). She gained popular support by advocating Buddhism but ruthlessly persecuted her opponents within the royal family and the nobility. In October 695, after several additions of characters, her imperial name was definitely set as Emperor Tiance Jinlun Shengshen (天冊金輪聖神皇帝), a name which did not undergo further changes until the end of her reign.
Republic of China (on Taiwan)
On February 20, 705, now in her early 80s and ailing, Empress Wu was unable to thwart a coup, during which the Zhang brothers were executed. Her power ended that day, and she had to step down while Emperor Zhongzong was restored, allowing the Tang Dynasty to resume on March 3, 705. Empress Wu died nine months later, perhaps consoled by the fact that her nephew Wu Sansi (武三思), son of her half-brother and as ambitious and intriguing as she, had managed to become the real master behind the scenes, controlling the restored emperor through his empress consort with whom he was having an affair.

Evaluation
Tiānshòu (天授): Oct. 16, 690 - Apr. 21, 692 (18 months) Rúyì (如意): Apr. 22 - Oct. 22, 692 (6 months) Chángshòu (長壽): Oct. 23, 692 - Jun. 8, 694 (19 ½ months) Yánzài (延載): Jun. 9, 694 - Jan. 21, 695 (7 ½ months) Zhèngshèng (證聖): Jan. 22 - Oct. 21, 695 (9 months) Tiāncèwànsuì (天冊萬歲): Oct. 22, 695 - Jan. 19, 696 (3 months) Wànsuìdēngfēng (萬歲登封): Jan. 20 - Apr. 21, 696 (3 months) Wànsuìtōngtiān (萬歲通天): Apr. 22, 696 - Sept. 28, 697 (17 months) Shéngōng (神功): Sept. 29 - Dec. 19, 697 (2 ½ months) Shènglì (聖曆): Dec. 20, 697 - May 26, 700 (29 months) Jiǔshì (久視): May 27, 700 - Feb. 14, 701 (8 ½ months) Dàzú (大足): Feb. 15 - Nov. 25, 701 (9 months ½) Cháng'ān (長安): Nov. 26, 701 - Jan. 29, 705 (38 months) Shénlóng (神龍): Jan. 30 - Mar. 3, 705 (Zhou dynasty was abolished on March 3, 705, and the Tang Dynasty was restored that same day, but the Shenlong era continued to be used until 707)