 By 1500, Lefèvre had begun to produce more philologically oriented editions—typically he placed the newer translations alongside the traditional medieval versions, with his own commentary and occasional emendations informed by his modest command of Greek. The earliest example of this method was his three-fold edition of Aristotle’s Nicomachean Ethics (1497), which included the medieval Latin version along with the translations of Johannes Argyropolus and Leonardo Bruni. This approach also defined Lefèvre’s ground-breaking editions of the Psalms (1509), the letters of St Paul (1512), and Euclid’s Elements of Geometry (1517a).