Scholars have often treated the concept of xiao as an unchanging notion with a transparent meaning. In the West, the translation “filial piety” has reinforced this tendency. By endeavoring to ascertain the precise meaning of the term in pre-Qin texts, this paper shows that xiao had multiple meanings and was constantly being reinterpreted to suit new social and political circumstances. In the Western Zhou, it was inti¬mately related to the cult of the dead and its recipients extended well beyond one's parents or grandparents. The ru of the Warring States emphasized that it meant obedience and displaying respect, and made parents the sole recipients of xiao. By the late Warring States, ru recast xiao not only as obedience to one's parents, but also as obedience to one's lord. Filial sons were reinvented as loyal retainers to meet the needs of the newly emerging bureaucratic state.