(1462-1516) Author of occult works including the De Lapide Philosophico of which Joseph Curwen owned a copy and the Poligraphia, which Armitage consulted at Miskatonic University's library.
Actually, this is Johanne Trithemius (also Tritheim), the German abbot of Spanheim and a friend of Henry Cornelius Agrippa von Nettesheim (1486-1533-5), the famed occultist commonly called 'Agrippa.' Besides his knowledge of medicine (Paracelsus was a student of his), Trithemius wrote a number of works on alchemy and magic. His witch hunting books: "Antipalus Maleficiorum," and the "Liber Octo Quaestionum," classify demons and call for the destruction of witches. Also a work entitled "De Setem Secundiis, id est. Intelligentiis, sive Spiritibus, Orbes post Deum Moventibus, &c." Cloniae, 1567, in which he is called 'Jaonnis Tritemii, Abbatis Spanheymensis'. He accredits himself with the exorcism Mary of Burgundy, wife of Emperor Maximilian. It is also interesting that Abbot Trithemius is one of the references to the actual existence of a Doctor Faust, having written contemptuously of him in a 1507 letter. Also his "Monas Hieroglyphica" had a profound effect on Dr. John Dee.
As for the work attributed to him by Lovecraft, Poligraphia is apparently real but we have found not mention of De Lapide Philosophico being his work (though titles often change) but a volume under the title "Lapis Philosophicus seu commentarius in 8' Lib: phys: Aristot: in quo arcana Physiologiae examinator" was written by John Case and published in 1599.
("The Case of Charles Dexter Ward," "The Dunwich Horror," "The Evil Clergyman")
See also: Poligraphia and De Lapide Philosophico
The Steganographia of Trithemius (the great occult teacher of both Agrippa and Paracelsus) was written at the end of the fifteenth century, and became one of the most influential and notorious of occult texts throughout the sixteenth and seventeen th centuries. It works on two levels - as a grimoire or book of conjuration of spirits, and simultaneously as a code book - and contains lists of spiritual messengers associated with the divisions of space and time, a Cabalistic Angel magic. The Steganographia which circulated secretly in manuscript during the 16th century was highly valued. John Dee, whose Enochian system of angelic magic was influenced by the Steganographia, noted that 'One Thousand Crowns' had been offered for a copy of this work. On one level it reveals ways of encoding secret information in outwardly innocent texts, and thus the publication of this item will have a considerable impact upon our view of the ways in which the esoteric orders of the 16th and 17th centuries may have conveyed information and preserved their secrets.
This volume includes Books I and III of the Steganographia, together with an extract from Gustavus Selenus' Cryptomenytices et Cryptographiae, providing an analysis of the method of encoding in the Steganographia.