From
李延年《
北方有佳人》(Li Yannian, Western Han, ~110 BCE), a song performed before Emperor Wu of Han introducing his own sister (later Lady Li,
李夫人):
北方有佳人,
绝世而独立。
一顾倾人城,
再顾倾人国。
宁不知倾城与倾国?
佳人难再得 (In the north there is a beautiful woman, peerless and standing alone. One glance topples a city, a second topples a state. How not know a city-toppler, a state-toppler? — a beauty like this comes once). The song is the origin of the phrases
倾城 /
倾国 /
倾城倾国 (devastating beauty).