Though it is well-known that Martin Luther stood in some connection to the late medieval theologians of his Order and that he intensively studied Augustine’s works in the mid-1510s, the exact nature of the influence either or both exercised upon the development of his theology is disputed. Arguably his adoption of advanced anti-Pelagian convictions aligns him with Gregory of Rimini contra pelagianos modernos in the realm of scholastic theology, while the pastoral theology he imbibed from Staupitz places him in a living tradition of “Augustinian Frömmigkeitstheologie” within the O.E.S.A. (the Hermit Order of St. Augustine). However, the most important impetus Luther received from late medieval Augustinianism was its determination to do theology in conversation with Augustine’s own works. Probably in 1514, Luther read the anti-Pelagian writings contained in the 1506 Amerbach edition of the Opera Omnia, and made his own both the iustitia passiva from sp. litt. 9.15 and the nexus of doctrines associated with residual “sin” in the baptized, which was increasingly emphasized in Augustine’s later works against Julian. Though young Friar Martin’s “Augustinianism” shifted in several respects, it possessed an enduring significance in Luther’s evangelical theology.