This is a case study of one of the best-known fake translations in Chinese history—Dayun Sutra. The common belief is that a female ruler ordered its production as a menas to justify her reign. This article traces the accounts of this event given in China's dymastic histories and Buddhist histories, as well as developments and new information revealed in the 20th century. Through an analysis of the reasons for the condemnation of this text, the norms which control the evaluation of translated texts are revealed.