Wu Zetian (武则天, 武則天, 武后, 天后 , 則天皇后, or 則天順聖皇后 depending on who and when you asked) wanted to be Empress (皇帝) of China so badly that she started a dynasty that consisted of just her to do it. The Zhou (周) Dynasty did not last long, but it made up for it in inter-familial assassinations and jackbooted secret police, so Wu should be proud of her accomplishment regardless.
Wu was born in Lizhou (利州), 625. As a girl, she preferred reading about history and politics to doing needlepoint, and what aspiring dictatress wouldn’t? When she was about thirteen, she attracted the attention of Emperor Taizong (唐太宗) of the Tang Dynasty (唐朝), and when he died, she was passed down to his son, Gaozong (唐高宗). He really took a shine to her, making more and more of his decisions. Wu was initially allied with Gaozong’s wife against another concubine, but the Empress was later blamed for the murder of Wu’s infant daughter and removed. The cynical might call this a fortunate tragedy.
As new Empress, Wu’s power increased as Gaozong became more and more sick with a mysterious illness. It was probably just her luck again. Luckier still, her political opponents all seemed to be guilty of unspecified crimes and subject to arrest, exile, or worse. After Gaozong died, even her sons, when they started getting imperial ideas of their own, quickly found out that they were traitors to China and exiled. Poor Zhongzong (唐中宗) only got to rule for six weeks.
Finally sole ruler of China, Wu was able to do everything she wanted, which seemed to consist of transforming China into a police state that encouraged citizens to secretly inform on each other and which relentlessly arrested, tortured, and killed anyone suspected of opposing her. This continued for some decades.
While Confucian experts expressed grudging admiration for her methods, they frowned on her breach of normal gender roles. If only she’d been born male, her ruthless political machinations and oppression could have made her the ideal Emperor. As it was, the establishment eventually rallied around Zhongzong, who deposed his mother, re-established the Tang Dynasty. He ruled weakly for several years (when his wife let him) then died: exactly the kind of strong male leadership the Confucians were looking for. Literally sick of the whole thing, Wu died before she had to see the whole mess play out.
Wu Zetian proved that living in a patriarchal society couldn’t prevent you from becoming a ruthless matriarch, if you really applied yourself and didn’t like your kids that much.