The “Twelve Labours” of Hercules are among the topics most often associated with the illustrious half-god of Graeco-Roman mythology. This series of heroic deeds includes the defeat of a monstrous lion that ravaged the countryside of Nemea in southern Greece, an episode from the life of ancient Hercules that was handed down to medieval Europe through the works of classical authors, such as Virgil, Ovid and Statius, and their commentators. As is often the case, this process of textual transmission gave rise to variation and multiple interpretations: the sole Nemean lion is, in some instances, replaced by a pair of two felines or even a leonine trio, a phenomenon that can be observed both in text and iconography. The present contribution aims to elucidate the history of a particular variational pattern involving three Nemean lions, as seen in Raoul Lefèvre’s 15th century Recoeil des Histoires de Troyes. By tracing the evolution of this particular version of the episode, we will consider commentaries, mythographic treatises and historiographical compilations.