This is an article on Hermes Trismegistus originally written in
response to the role-playing game _Ars Magica_, which described
"Hermetic mages" as the successors to the Roman priesthood
of Mercury.  (It's a decent game other than this, but...)  Ken
Hite wrote the following to explain who _really_ put the
Hermes in Hermetic, and thus:

                        Hermes Thrice-Blessed, or
                        _Roman_ Priests of _Who_?

                         by Kenneth Allen Hite

        When looking at the rules and supplements to _Ars Magica_, one
becomes aware of two great truths.  The first is that the authors have
put together an incredibly good role playing game that captures
perfectly the feel of medieval magic, especially as seen through our
20th-century lenses.  The second is that the authors have no idea who
"Hermes" is, in the context of medieval magic.  They seem to think
that what is referred to as the "Hermetic tradition" descends from the
worship of the Greek god Hermes through the cult of his Roman eidolon
Mercury to the post-Roman survivals of knowledge in the Middle Ages.
This is incorrect.  The "Hermetic tradition" of Western magic, which
is one of the most powerful forces in the "underground stream" of
Western culture, has less to do with the Roman god h Mercury than it
does with hermetic sealing.
        The "Hermes" referred to is Hermes Trismesgistos "Hermes the
Thrice- Great", who was conflated with the Egyptian god Thoth.  When
the Greeks came to Egypt, they were incredibly impressed by the
ancient wisdom of the Egyptian priests.  So impressed, that they
immediately plastered their gods' names all over the older Egyptian
ones in the grand old syncretic Greek tradition.  Hence Amon became
Zeus-Amon and Thoth, god of letters and sciences, became Thoth-Hermes
(since Hermes invented the Greek alphabet, don't you know).
        Here is where Game Truth and Historical Truth diverge.  In
Game Truth  (where diseases are caused by an imbalance of humors and
the sun goes around the Earth) Hermes Trismesgistos was a very
powerful ancient mage.  He was _not_ a god.  No reputable medieval
magus believed in polytheism -- most, like John Dee, were devout (if
goofy) Christians.  In his writings, collectively called the _Corpus
Hermeticorum_, Hermes describes himself as "Philosopher, Priest, and
King".  Hence, he was human.  An incredibly powerful sorceror, to be
sure, but not a god.  His exploits included building the Pyramids,
designing the Hanging Gardens of Babylon, teaching Pythagoras, and
generally doing everything worth doing in antiquity.  He also invented
the Egyptian alphabet and while doing that and building the odd
pyramid, became the inspiration for the legends of Thoth.  After his
death (or occultation) he was worshipped as a god, much as Alexander
the Great was.  Speaking of Alexander the Great, it was he who
discovered the _Emerald Tablet_ (on which was written the whole
knowledge of magic in about two paragraphs -- apparently it wasn't
what he said, it was how he said it) clenched in the mummified hands
of Hermes Trismesgistos him self.  Other legends say he discovered it
in the hands of the ancient magician Apollonius of Tyana, but since
Apollonius as born four hundred years after Alexander died, most
scholars doubt this theory.  Still other legends say the Tablet was
discovered by Sarah, wife of Abraham, which would make Hermes dead
before he built the Hanging Gardens.  Anyway, the knowledge on the
Tablet and in Hermes T's other writings (17 or so known books plus
commentary) was what was called "Hermetic Science".
        In Real History, the whole thing was faked up about 200 AD by
the Gnostic community in Alexandria who were big with the alchemists
who lived around there and then.
        Either way, the _Corpus_ survived in Greek libraries and later
in the Arab world.  It was, however, lost in the West except for the
hints and allusions that bled through from Arabic contacts.  The
itinerant occultist adept al-Farabi (890?-954) is described as
"Hermetic", and it is likely that the alchemical writings of Geber
(721-766), Rhazes (850-924) and Avicenna (980-1036) draw on the
_Corpus_ to some extent.  The Arab alchemistic writings began to
filter into Europe following the Papacy of Sylvester II (999-1003) and
were eventually disseminated such that the legend of Hermes
Trismesgistos achieved a certain degree of recognition.  The actual
_Corpus_ did not become available to the West until 1460, when the
documents salvaged from Constantinople surfaced in Florence.  Their
translation in 1471, by Marsilio Ficino, set off the great explosion
of Renaissance magic personified by Dee, Trithemius, Agrippa, and
Paracelsus.
        This then, in a nutshell, is the "Hermetic Tradition": either
the Game Truth (2500 BC Hermes T builds Pyramids, is Thoth, lives
until c 550 BC when he finished off the Hanging Gardens, trained
Pythagoras, and died in a cave clutching his Emerald Tablet.
Discovered by Alexander, put in Library, alchemists study it,
knowledge lost with Fall of Rome, rediscovered in Dark Ages by
Vergil/Bonisagus/Aethelstan, spread by Order to this day) or the Real
Truth (200 AD Heretical alchemists work out consistent philosophy,
ascribe it to mythical figure to get credibility, knowledge survives
in alchemical tradition in Arab lands, stored in Byzantium, filters
into Europe c900-1250 AD from Spain, Crusades, Sicily, rediscovered in
1471, all hell breaks loose).
        This is so much cooler that one wonders why anyone would drag
those stuffy old Roman priests into it at all.  "Hermetic sealing" by
the way, comes from an alchemical practice named for Guess Who.

As above, so below.

Kenneth Hite, LHN
hit2@midway.uchicago.edu