The aim of this paper is to reflect on the translation approach of two Latin authors of Late Antiquity, based on a series of their paratexts: Jerome (Ad Pammachium de optimo genere interpretandi, 57) and Calcidius (Introductory Epistle and preface of the Commentarius in Timaeum). Since both are dedicated to the translation of texts that could be considered “sacred” in Late Antiquity (the Bible, Plato’s Timaeus), their translation practices are mainly met with a tension between the poles of “tradition” and “innovation”, which can be re-read from a Translation Studies’ perspective through the categories of “fidelity” and “freedom” / “equivalence”. In short, what is at stake is the construction of discursive and moral authority (auctoritas), which guarantees the effectiveness of its task, on texts that project a particular character: the sacred.