The aim of this work is try to interpret and comment from a historical point of view a passage of Ammianus’ Res Gestae in which Julian is defined immaculatus. A new theory will be proposed that mediates the two already existing ones, bringing to light some additional data. In order to interpret these data historically, starting from Ammianus, we will tackle a thematic-comparative path in which we will analyse some historical figures quoted by Cicero, Tacitus, Cassiodorus, Ennodius and others who, with their being either maculi or sine macula, influenced in a positive or negative way the fate of the Roman state.

Keywords: macula, Domitian, lexicon, Primigenia, Julian, immaculatus.