Honorius Augustodunensis ("of Regensburg"), born perhaps in the 1070s, was a native son of southern Germany or Austria who pursued his studies in England with St. Anselm of Canterbury. Under Anselm's influence he became a Benedictine monk before returning to Germany in the opening years of the twelfth century. During his life-long monastic career he blossomed as a prolific writer. He died around 1140. The epithet "of Autun," as a translation of "Augustodunensis," was applied to him by scholars a century ago and earlier, but it has long been discredited, and the meaning of "Augustodunensis" remains a mystery. Although Honorius has been appropriately described as an enigmatic figure, his strong influence on Western theologians is widely recognized. Despite his large corpus, now known to consist of approximately thirty texts (but almost certainly more), Honorius Augustodunensis is the most unjustly neglected writer of the twelfth- century renaissance. Although he is best known as a popularizer, he also composed a major philosophical text, The Key to Natural Philosophy ( Clavis physicae), ca. 1125-30. Taking the form of a dialogue between master and disciple, the Clavis is an abridged paraphrase of Eriugena's Periphyseon, the most radical work of Neoplatonic thought in the time frame between pseudo-Dionysius and Meister Eckhart. Honorius treats such topics as the unknowability of God, apophatic and cataphatic theology, the primordial causes, the cosmological process of creation and return, human and angelic nature, the Fall, the four elements, and the findings of ancient astronomers. Although Eriugena was condemned for heresy in the thirteenth century, Honorius managed to escape that censure. The Key to Natural Philosophy thus became the chief conduit of the Carolingian philosopher's thought in the later Middle Ages, influencing readers from Eckhart through Nicholas of Cusa.