This volume analyzes the fortune of books I–V of Diodorus Siculus’ "Bibliotheca historica" in the 15th and 16th centuries, based on the study of the first two translations into Italian. Published anonymously, they both derived from Poggio Bracciolini’s 1449 Latin version. The study investigates the history of these two texts, reconstructing, as much as possible, the context of their production, and offers a critical parallel edition.