This may be a form of extended naval gazing, but questions like these often come to me while I'm out on my morning runs:
What religion are Magi?
Obviously, this is a question with no single answer. In theory a maga could be just about any religion, and citations are made in the books of several.
Criamon have their own weird magic religion, of course.
Historically, Hermeticism as a religion is a curious religion/philosophy developed in Western Europe. It would take an entire essay just to discuss it, but I'll just quote from (and link to) Wikipedia:
"The tradition claims descent from a prisca theologia, a doctrine that affirms the existence of a single, true theology that is present in all religions and that was given by God to man in antiquity."
It's always been chiefly intertwined with magic, from its conception to its renaissance (literally, in 1460 in the Renaissance).
The curious part about the Hermetic tradition in Ars Magica is how devoid it is of this divine heritage. Indeed, the Order seems largely to be about stripping religious iconography. Mention is made of Hermes (Order of Hermes, after all) but little attention is given to this fact. I recall reading in the old Provencal tribunal book that there was one Covenant which was essentially a literal cult for Hermes - something which irritated non-pagan magi to no end. Mention is also made in the Divine book of how magi incorporate pagan traditions and how certain Holy Mages strip that from it.
There also comes a problem. The Problem of Three (or more) religions.
If the Pope, the Caliph, and the Exilarch enter a bar together, they will size each other up with their 25 magic resistance (+ dominion + relics yada yada) and argue this and that about Jesus and prophecy and end times and such, but it would be impossible to deny what they have always denied, which is that each tradition canonically is an equal conduit to God.
But what is a maga, observing in and with an eye to the deeper nature of the world, to think of such a meeting? From an outsider's perspective, if each of three contradicting traditions have equally valid claims to power, then they must all three must be wrong about major aspects of their core beliefs. And then don't even get me started on Zoroastrians or that one tribe on the Hesperides.
So, while magi can be Christians, Jews, Muslims, or whatever, but when they look out into the world, study it, and find these perfectly valid alternatives - is that not a faith-shattering event? How can one reconcile being an exclusive Christian and believing in the Trinity and the full and co-equal divinity of Jesus Christ when an Imam claiming Jesus was merely a prophet and some fellow named Mahomat or whatever has a far better claim to divine truth?
Further complicating this is the Empyreal problem - where we have divine auras totally stripped of human religious symbolism. Angels are involved with these religions but themselves adhere to none.
Magi can also travel to different realms where they see that not all fits in cleanly with the Bible et all.
This brings me back around to historical Hermeticism, and what I think is the likeliest answer to my question:
Most Hermetic magi are Hermetic.
They believe that there is one creator from which the universe erupted, and that universe emanates in different stages down from that divine source. The deities of magic are themselves emanations of this divine creator, not pagan lies, and Hell is the abode of negation or concealment from divine purpose.
In this view, magic is not only an acceptable pursuit, like a tradesman, but it is a fully valid act of unification with divine purpose. Not only that, but most magi probably believe that learning to embrace magic is indeed a vital aspect of their religion.
Mages require no priests and no doctrine because they are themselves the priestly class. Grogs may also subscribe to these ideas and look to magi for guidance.
Outsiders regard them as heretics, if they find out, and so much of the religion is shrouded in symbolism and secrecy.
Since variety of the spice of life, I propose a couple factions within this weird mystery religion:
Neoplatonics
Generally believe in the main principles of the unified religion. Hermes Trismegristus is a central figure. Heavily scholarly, these magi believe that the purest form of magic is the purest form of divinity, and so are very much into plumbing the secrets of the universe for truth.
They believe that earthly religions are not exactly wrong, but not right.
Neoplatonics do not reject the pagan gods. Instead, they see them as necessary aspects of the world, and are themselves paths to divine knowledge.
Some Neoplatonics may go so far as to say that the pagan gods are all literally different faces of god, or perhaps emanated Aeons who have a deeper nature.
Hermetic Theurgy from Mystery Cults is probably an excellent resource for these people.
Gnostics
A much darker form of this belief system, not only do they think that all earthly religions are partly wrong, they think that they are in fact corrupted. They point to the scandals of priests, imams, and caliphs, the terrible way peasants are treated, the way the Dominion aura seems to crush dissent and subsume people into a very obedient form and say that this cannot possibly be the correct way to go about it.
Gnostics believe that the god of the churches, mosques, and synagogues is in fact the Demiurge, a lesser (or even evil) divine entity responsible for creating the material world. His agents are in fact demons and the Dominion aura is just obfuscation. The true Divine auras are Empyreal, which emanate from the true good god and his agents who resides beyond the material plane.
Some gnostics may even go so far as to say that people who don't embrace magic are doing it wrong, that if you blindly accept the teachings of the church you will simply be reincarnated back into the mundane prison. Only through magic can one unlock the divine spark within - the Gift, doubtless - and ascend.
Critics of the gnostics point out inconsistencies - for instance, that Empyrean and Dominion do not seem to conflict. Priests gain the same benefits, angels aren't in conflict, so on and so forth.
Origenists (courtesy of Ramidel)
These are already canonical to the Order of Hermes, and aside from the astrological beliefs, they hold to the doctrine of the Perfectibility of Man and of Universal Reconciliation. No soul is ever eternally damned; instead they reincarnate until they achieve Heaven; in this, Origen's beliefs are semi-Gnostic, but do not admit to the idea of an evil Demiurge. They would be much more likely to hold to the idea that Christianity is "right," but with influence from Hermeticism they might branch out into a new religion entirely.
Criamon
Already extensively covered in their own Mystery Cult. The ideas here can add a little flavor, though.
Tremere
A non-hermetic faction. They refuse to swear oaths to Hermes. Their position on religious unity is unclear.
Diedne
Also non-hermetic, where they exist. Most if not all are still solidly pagan.
Consequences:
It may be that magi who follow Hermeticism are able to strip the Dominion penalty in some fashion, similar to how Learned Magicians do it. Aside from that, this is mostly flavor.
Now, I know that it's stated explicitly several times that Criamon and the like are wrong. The Rival Magic book even sought to reassure me that Ragnarok could never happen. Honestly, I think these are boring and deplete from their interest - I'd rather find out in play what's right and what's wrong, and have that be relevant to my particular Saga.
Curious to hear thoughts, especially from scholars of Hermeticism, and how I might better integrate authentic traditions.