The influence of Greek sources on the Arab philosophers is both obvious and important. What is less clear is how the quality of the translations from which the philosophers worked affected their understanding of the points that the Greek writers were making. This article investigates one small but self-contained topic from within the field of translation literature, covering the translations of poetic quotations in the Rhetoric of Aristotle in its Arabic translation, together with an analysis of the types of mistakes to be found there. In itself this is of no more than curiosity value, but an application of the lessons to be learnt here to a linguistic study of Arabic philosophical commentaries, and, by extension, to philosophical theory, will be of clear importance.