From Sima Qian's (
司马迁) Han-dynasty 《
报任安书》 (Letter to Ren An). The full line is 『
人固有一死,
或重于泰山,
或轻于鸿毛』— 'everyone must die, but some deaths are weightier than Mount Tai, and some lighter than a goose feather.' Sima wrote it while enduring palace castration rather than suicide, explaining why he had to live to finish the 《
史记》 (Records of the Grand Historian).