Hermetism refers to a Greco-Egyptian pagan mystical sect, based on the Hermetic Corpus, also known as the Hermetica, a group of tracts composed in Hellenic Alexandria in the first century C.E To be distinguished from its Renaissance and modern offshots, generally known as Hermeticism.
According to literary scholar Harold Bloom, "The Hermetists were Platonists who had absorbed the allegorical techniques of Alexandrian Jewry, and who developed the Jewish speculation concerning the first Adam, the Anthropos or Primal Man, called the Adam Kadmon in Kabbalah, and 'a mortal god' by the Hermetists...."
The Hermetic Corpus became available to the West in 1460, when the documents salvaged from Constantinople surfaced in Florence. Their translation in 1471, by Marsilio Ficino, set off the great explosion of Renaissance Hermeticism as embodied in John Dee, Giordano Bruno, Tommaso Campanella, Johannes Trithemius, Heinrich Cornelius Agrippa, Robert Fludd, and Theophrastus Bombastus von Hohenheim Paracelsus.
