Can we make trans history before the emergence of first-person narratives, and before the very conceptualization of trans issues? The hypothesis this paper develops is that the study of premodern gender transitions can teach us other ways of looking at gender that complicate our current perception, and open up perspectives for future trans people. The case of Eugenius-Eugenia of Rome is one of a series of around thirty lives of saints devoted to historical and/or fictional figures who underwent a transmasculine gender transition, which was at the heart of their path to sainthood. Based on archaeological data from the 3rd century, texts from the 5th century and an iconographic tradition from the 6th to the 16th century, we can attempt to trace the perception and reception of this figure in terms of gender, according to geographic areas.