Chen Yuanyuan lived near the end of the Ming Dynasty, and was a concubine of Wu Sangui. Her actual historical significance is disputed, although it is largely believed that Chen was pivotal in Wu Sangui's campaigns after the fall of the Ming.
Wu Sangui was a Ming Chinese general who was instrumental in the Qing Dynasty conquest of China proper in 1644. After the rebel leader Li Tzu'cheng took Peking and the Ming emperor was killed, Wu Sangui opened the gates of the Great Wall of China at the Shanhai Pass to let Manchu soldiers into China proper. Popular legend relates that Li Tzu'cheng had captured Wu’s concubine, the famous beauty Chen Yuanyuan, and that Wu asked the Manchu for assistance against his forces.
In the classical novel Water Margin, Li Shishi encounters the outlaws from Liangshan Marsh on two occasions; on the second, more important encounter, she befriends Yan Qing and agrees to become his sworn older sister. She then promises Yan Qing then she will tell the emperor about the outlaws' plight and desire to be granted amnesty.