A conversation with Daphne Penna (University of Groningen) about Byzantine law, or (what it really was) the Greek-language phase of Roman law. We talk about the study of east Roman law, its experts (both then and now), and the interaction of Greek and Latin in legal texts. What did the law do and what do we learn from studying it? For an accessible introduction to the main sources, see the anthology edited by Daphne Penna and Roos Meijering, A Sourcebook on Byzantine Law: Illustrating Byzantine Law through the Sources (Brill 2022).