  For the long commentary tradition, from John of Scythopolis to Aquinas and Ficino, see bibliography 2 below. St. Gregory the Great refers to Dionysius in his own commentary on the angels and probably had the complete works at Rome. But the study of Dionysius did not take off in the Latin West until the Byzantine emperor Michael the Stammerer sent a copy of the Dionysian corpus as a gift to the Frankish king Louis the Pious in 827. This copy served as the source of the first translations of Dionysius into Latin. The first translation, made around 838 by Hilduin, abbot of a monastery near Paris (who identified Dionysius not only as St. Dionysius the Areopagite but also as the first bishop of Paris), was so unintelligible that Charles II asked the great Irish philosopher, John Scottus Eriugena, to make a new translation that he completed in 862 and that was subsequently revised with clarifications in 875. The influence of Dionysius is profound in Eriugena’s own thought as it would be later in the Franciscan tradition (especially Grosseteste and Bonaventure) and also to a lesser extent in the Dominican (both Albert and Aquinas wrote commentaries). In fact, the abiding-procession-return triad may be said to form the essential structure of Aquinas’ unfinished masterpiece, the Summa Theologica. The influence of Dionysius’ ideas pervades not only the Italian and English Renaissance, but also the Rhineland mystical writers, such as Meister Eckhart (d. 1327), Tauler (d. 1361), Ruysbroeck (d. 1381), Gerson (d. 1429), and later Denis the Carthusian (d. 1471) and Nicholas of Cusa (d. 1464) (whose work On Learned Ignorance owes a debt to Dionysius’ agnosia or unknowingness, as does also the anonymous author of the Cloud of Unknowing) and the great Spanish mystics, for example, St. John of the Cross (d. 1591). In the Greek East, Dionysius’ On the Ecclesiastical Hierarchy inspired a series of liturgical commentaries, beginning with the Mystagogy of Maximus the Confessor (d. 662) and continuing with works by Germanus of Constantinople (d. 733) and Nicholas Cabasilas (d. 1390). Dionysius played a major role in the Palamite controversy of the 14th century, cited both by Gregory Palamas (d. 1359) and by his opponents. In the modern world, Dionysius has received less attention, though he is of some importance for 19th century German Idealist thought and also to a lesser extent for English and American Romanticism. In the so-called “postmodern” world, however, two thinkers who have written about Dionysius with great insight are Jean-Luc Marion and Jacques Derrida. Derrida, in particular, has been one of the few contemporary philosophical thinkers, if not the only one, to realize the importance of Dionysius in relation to deconstruction (a term he does not use himself) and to explore the complex nature of prayer, address, and denial in the context of the necessarily deceptive and open-ended possibilities of negative theology.