Xi Shi (Chinese: 西施; pinyin: Xī Shī, 506 BC – ?) was one of the renowned Four Beauties of ancient China. She was said to have lived during the end of Spring and Autumn Period in Zhuji, the capital of the ancient State of Yue. Her name was Shi Yiguang (施夷光).
Xi Shi's beauty was said to be so extreme that while leaning over a balcony to look at the fish in the pond, the fish would be so dazzled that they forgot to swim and sank away from the surface. This description serves as the first two characters of the Chinese idiom 沉魚落雁, 閉月羞花 (pinyin: chényú luòyàn, bìyuè xiūhuā),[clarification needed] which is used to compliment someone's beauty.
The Story of Xi Shi 
King Goujian of Yue was once imprisoned by King Fuchai of Wu after a defeat in war, and Yue later became a tributary state to Wu. Secretly planning his revenge, Goujian's minister Wen Zhong suggested training beautiful women and offering them to Fuchai as a tribute (knowing Fuchai could not resist beautiful women). His other minister, Fan Li, found Xi Shi and Zheng Dan, and gifted them to Fuchai in 490 BC.
Bewitched by the beauty and kindness of Xi Shi and Zheng Dan, Fuchai forgot all about his state affairs and at their instigation, killed his best advisor, the great general Wu Zixu. Fuchai even built Guanwa Palace (Palace of Beautiful Women) in an imperial park on the slope of Lingyan Hill, about 15 kilometres (9.3 mi) west of Suzhou. The strength of Wu dwindled, and in 473 BC Goujian launched his strike and put the Wu army to full rout. King Fuchai lamented that he should have listened to Wu Zixu, and then committed suicide.
In the legend, after the fall of Wu, Fan Li retired from his ministerial post and lived with Xi Shi on a fishing boat, roaming like fairies in the misty wilderness of Taihu Lake, and no one saw them ever again. This is according to Yuan Kang's Yue Jueshu (越绝书). Another version, according to Mozi, is that Xi Shi eventually died from drowning in the river. (西施之沈，其美也)
The West Lake in Hangzhou is said to be the incarnation of Xi Shi, hence it is also called Xizi Lake, Xizi being another name for Xi Shi, meaning Lady Xi. In his famous work of song poetry, Drinks at West Lake through Sunshine and Rain (飲湖上初睛居雨), renowned scholar Su Dongpo compared Xi Shi's beauty to the West Lake.
Imogen Heap released a song in 2012 titled Xizi She Knows after spending time in Hangzhou, China.
Other references 
There is another well-known figure of unknown origin, probably fictional and parodical, named Dong Shi (東施). The "Dong" in her name means "east" contrasting to Xi Shi's "Xi", which means "west". Apart from her name, she is said to be the exact opposite of Xi Shi in being extremely ugly. This in turn has created the saying "Dong Shi imitates a frown" (东施效颦), whereas Dongshi, being ugly and thus inviting no suitor, emphasized her own ugliness while imitating Xishi's look of sexualized frailty and suffering. The saying has taken on a meaning to signify one's vain attempt imitating another only to emphasize one's own weaknesses.
A tongue twister that works best in Mandarin references XiShi: 西施死時四十四，四十四時西施死。(XīShī sǐ shí sì shí sì, sì shí sì shí XīShī sǐ.) It means Xishi died at (the age of) forty-four, at (age) forty-four Xishi died.