Chen Yuanyuan

Chen Yuanyuan (c. 1623–1689 or 1695) was a Chinese courtesan who later became the concubine of military leader Wu Sangui. In Chinese folklore, Chen’s capture by the Shun army during Li Zicheng’s conquest of Beijing in 1644 prompted Wu’s fateful decision to open Shanhai Pass to the Manchu army in order to form a joint force to rescue her, an act that sealed the downfall of the Ming dynasty and the founding of the Qing. Provided by Wikipedia