International audienceThis paper focuses on the presence of Jerome as a source for the Liber Glossarum. My work provides an overview of this presence (with detailed tables displaying lists of glosses and Jerome's quoted works) and a discussion about problems and opportunities connected with this kind of research. In the last section, the paper offers the analysis of a specific entry-LG, SV 373-374 (Substantia) – whose text is ascribed to Jerome by the Liber Glossarum, even though without any confirmation within his corpus of writings. I show how these two glosses actually contain a large portion of the Epistula de Substantia written by Potamius of Lisbon. The Liber Glossarum seems to be the earliest witness for Potamius' text.Mon article es...