Abstract An overlooked fragmentary Latin text preserved in the Corpus of Roman Land Surveyors proves to be a translation of a lost branch of the Aratean commentary tradition. Stripped of the classicizing veneer mistakenly applied by earlier editors, the fragment can be recognized as the work of an unknown and inept late-antique Translator, perhaps working within a generation of the fragment’s earliest manuscript witness, the Codex Arcerianus. The branch of the commentary tradition used by this Translator made use of Euclid ‘the Sicilian’, an authority now absent from the surviving tradition: if this Euclid is identical with the famous geometer, as argued here, we may have radical new evidence for his homeland, hitherto unknown. The Aratean manuscript used by the Translator was equipped with interlinear Latin glosses and with illustrations of a type otherwise unattested in the surviving Aratean tradition.