The literature of Greek and Roman Antiquity handed down in manuscripts was exposed to the constant danger of texts being corrupted by manipulations not sanctioned by the author concerned. This can also be demonstrated in translations, for example if the text of a foreign-language book was altered by a translator without the original author's consent. The authors, however - i.e. those affected themselves -were highly conscious of their auctorial status and condemned the secondary manipulation of their works as a presumptuous attack on the integrity of the original text. The present study devotes itself to these practices of falsification and distortion using evidence presented by the authors concerned over a period stretching from Early Greece to the beginning of the Middle Ages.