Xi Shi as the oldest one of the four is historically less concrete. She is said to have hailed from Mt. Zhuluo 苎蘿萝山 (modern Zhuji 諸暨, Zhejiang) in the state of Yue 越. Xi Shi's father was a woodcutter who lived west of the village of Huansha 浣紗村 (hence her cognomen Xi 西 "west"). When her lord, King Goujian 勾踐 of Yue, lost his battle against the king of Wu in 494, he used the plan of his advisor Fan Li 范蠡, the so-called "strategy of the beauty" (meiren ji 美人計) and presented the King of Wu with Xi Shi and another beautiful girl called Zheng Dan 鄭旦. King Fucha was so charmed by her that he lost all about governing and declined the warnings of general Wu Zixu 伍子胥. His army was finally defeated by King Goujian.
It is also told that Xi Shi used to learn walking with utmost grace and trained on the city wall, so that everyone watched at her and was distracted from work. People event spent a lot of money to have a glance at her on the markets. After three years, people and king of Wu were so effeminated that it was easy for Yue to take revenge and destroy the state of Wu. Some stories say that she later became the wife of Fan Li, another story says that she drowned herself or was drowned for revenge.
Another story in the geographical book Wudiji 吳地記 goes that already on the way to Wu she had an affair with Fan Li so that she only arrived at the court of Wu three years later and gave birth to a child fathered by Fan Li.
An anecdote tells the story that once when she was sick she used to knit her eyebrows because of pain. The most ugly girl of her village imitated this behaviour and so became all the more ugly. As a counterpart of Xi Shi she was therefore called Dong Shi 東施 (Dong 東 being "east"), and the proverb Dong Shi xiao pin 東施效颦 means blind imitation with ludicrous effect.
The earliest historical references to Xi Shi appear in the regional histories Yuejushu 越絕書 and Wu-Yue chunqiu 吳越春秋. Tang period 唐 (618-907) poets often mentioned her as one of the most beautiful women on earth. The Ming period 明 (1368-1644) writer Liang Zhenyu 梁辰魚 wrote a novella called Huanshaji 浣紗記.
Some scholars are of the opinion that "Xi Shi" and "Zheng Dan" were originally not names of persons, but local (probably non-Chinese) words for "beauty" or "excellent".