Among the Arabs and in medieval Latin learning the reputation of Hermes continued not only as an alchemist, but as a fountain of wisdom in general. Roger Bacon spoke of “Hermes Mercurius, the father of philosophers.”[667] Daniel of Morley we have heard cite works of Trismegistus and distinguish between “two most excellent authorities,” the “great Mercury,” and his nephew, “Trismegistus Mercurius.”[668] Albertus Magnus cited “The so-called _Sacred Book_ of Hermes to Asclepius,”[669] an astrological treatise of which the Greek version has been mentioned in our earlier chapter on Hermes, Orpheus, and Zoroaster. And Albert’s contemporary, William of Auvergne, bishop of Paris, makes use several times[670] of the dialogue between Mercurius Trismegistus, “the Egyptian philosopher and magician,” and Asclepius from a _Liber de hellera_ or _De deo deorum_, which is presumably the Greek Ἱερὰ βίβλος. Trismegistus is represented as affirming that there is divine power in herbs and stones. In the _Speculum astronomiae_[671] Albert listed a number of bad books on necromantic images[672] by Hermes of which Christians were to beware: a book of images for each of the seven planets, an eighth treatise following them, a work on _The seven rings of the seven planets_, a book of magical illusions (_liber praestigiorum_),[673] and a book addressed to Aristotle. William of Auvergne seems to allude to the same literature when he twice repeats a story of two fallen angels from Hermes, citing his _Seven Planets_ in one case and _Book of Venus_ in the other.[674] Albertus Magnus also cites “books of incantations” by Hermes in his work on vegetables and plants;[675] and a _Liber Alcorath_ is ascribed to Hermes in the _Liber aggregationis_ or _Experimenta Alberti_ which is current under Albert’s name. The astrologer Cecco d’Ascoli in the early fourteenth century cites a treatise by Hermes entitled _De speculis et luce_ (_Of mirrors and light_).[676] These few instances of medieval citation of Hermes could of course be greatly multiplied but suffice to suggest the importance of his name in the later history of magic and astrology as well as of alchemy. [Sidenote: Astrological treatises.]