It is a cool idea especially knowing this: telegraph.co.uk/news/worldne ... China.html 
Actually you do need a completely different cosmology because the current underlying cosmology is Euro/christian centric (which is what it's built for) which is what I don't want.
If you're playing a game where the player characters are going to interact with that cosmology then I accept that you might want to redefine it into something that fits where you want to take the game.
If you're playing a game where the characters are not going to come face to face with the foundations of the universe then I don't see a need to delve that far. It doesn't matter whether the shadows on the wall really are cubes and spheres. If they look like cubes and spheres it's reasonable to treat them as such. Similarly, it doesn't matter whether you have two, five, or seven versions of Mythic Cathay, each in a different part of the Faerie Realm. They're all faerie and they can all be as different as you like. I guess it only matters when you take them to the "real" Mythic Cathay. And even then their understanding of the cosmos could still fit within the four realms if you're stretching things that far anyway.
If you take the setting to such a place that the three key religions as described in the book are broken down by revelation of this "other" underlying absolute truth of the universe, then you're playing a game where Mythic Europe is pretty remote from what's defined in the canon material. If you're doing that, make sure your players are all signed up for that particular journey - don't spring it on them, no matter how mind-blowing a reveal you might think it to be, your players, having opted to play in Mythic Europe, may not be so on board with it.
He was born 1254 Xavi. So just shortly after standard game era.
True.
Well in that case you can also try running it as we did, real world is as it is, myths and beliefs are exactly that, no more no less, but they may still be completely or partially true, either in the form of regio´s or as additions to the real world. Dragons might not be seen by more than a handful of people every few years, but they might still exist in plenty. We ran the Divine as a different kind of supernatural, basically the place of preference for "egocentric" deities, the kind that among other things tend to proclaim "im the only one there is".
With infernal in essence being against all other supernatural realms.
Well, it´s one more option at least.
Edit: Note, any potential multiposting is not my fault, hopefully i managed to delete the 1 or possibly 2 copies but kept getting "Internal server error 500" randomly so i cant really say for sure what worked and what didnt.
I know about marco polo. He is still relevant to the discussion given the public reaction when he reported what he had seen in his travels. 
Xavi
If only we could convince the writers of the game, or at the very least I could convince my fellow tabletop gamers that this is a GREAT idea to implement. It would satisfy my endless agitation with the idea of the Divine existing as represented in Ars.
As for Marco Polo, as of game time of 1220, the trips to Cathay are not unheard of, his dad was already doing merchant trips about this time right? And 40-60 years later Marco is writing about them? You know, I am on line I should just look it up but I am so lazy right now. 
You seem to think the writers of the game pick the cosmology, or themes of the books, and that's not correct. David Chart, the line editor, does.
Now, IMO, you won't convince him to change, but he's the guy, not the authors.
As to your preference, the problem is your brief way of putting things "All myths are true" doesn't actually say what you really want. Let's unpack it.
OK, so the most popular mythos in ME is a Judean fringe sect about a carpenter who conquered death and offers immortality to his followers. You do not wish it to be true, because it claims a monopoly on truth, and omnipotence for its skyfather.
The second most popular myth cycle in Europe is about a merchant who is given the Truth by an angel. His skyfather is also omnipotent.
If you go pagan, that's great, but again you get gods who are just utterly wrong in their self-perceptions. Anwyn thinks he's the lord of the dead. Pluto thinks he's the lord of the dead. Zeus thinks he's the skyfather. The Jade Emporer thinks he's the skyfather. When their followers meet, what happens? If both are true, then because each claims his role exculsively, actually niether is true - both are equally false. The Jade Emporer goes from being the skyfather to being one of many, many skyfathers. Anwyn goes from being Lord of the Dead to being Lord of the Gullible Welsh Dead, because if they weren't gullible, they'd choose a religion in which, in death, you become a God, not a serf.
That's what you are asking for, IMO, that all myths be false enough that they seem equally true when they clash. Faerie will do that for you now. THe problem is that it means if you are devoted to any of these gods, you are devoted to a thing which does not know its own limits, and so seems a bit silly when unbelievers point out that if the local skyfather doesn't give them what you want, there's another one up the road.
You seem to think the writers of the game pick the cosmology, or themes of the books, and that's not correct. David Chart, the line editor, does.
Now, IMO, you won't convince him to change, but he's the guy, not the authors.
As to your preference, the problem is your brief way of putting things "All myths are true" doesn't actually say what you really want. Let's unpack it.
OK, so the most popular mythos in ME is a Judean fringe sect about a carpenter who conquered death and offers immortality to his followers. You do not wish it to be true, because it claims a monopoly on truth, and omnipotence for its skyfather.
The second most popular myth cycle in Europe is about a merchant who is given the Truth by an angel. His skyfather is also omnipotent.
If you go pagan, that's great, but again you get gods who are just utterly wrong in their self-perceptions. Anwyn thinks he's the lord of the dead. Pluto thinks he's the lord of the dead. Zeus thinks he's the skyfather. The Jade Emporer thinks he's the skyfather. When their followers meet, what happens? If both are true, then because each claims his role exculsively, actually niether is true - both are equally false. The Jade Emporer goes from being the skyfather to being one of many, many skyfathers. Anwyn goes from being Lord of the Dead to being Lord of the Gullible Welsh Dead, because if they weren't gullible, they'd choose a religion in which, in death, you become a God, not a serf.
That's what you are asking for, IMO, that all myths be false enough that they seem equally true when they clash. Faerie will do that for you now. THe problem is that it means if you are devoted to any of these gods, you are devoted to a thing which does not know its own limits, and so seems a bit silly when unbelievers point out that if the local skyfather doesn't give them what you want, there's another one up the road.
In play, of course, the "gods" don't know they are wrong, and the characters don't know that the "gods" are wrong either. So, in play everyone says that they are right and everyone else is wrong, and before you know it either there is a crusade or somebody is burnt at the stake, or (just maybe) somebody converts to another faith. Which from a "realism" point of view seems to cover things about right!
Which is the the key to the whole issue I think. Sure, the players can read the rule-books and see that God / The Divine is right and all-powerful. But in play, all that the characters can see is that The Divine is more powerful than other realms, in some circumstances. In play, it looks like the priest is right about some things, but it also looks like the rabbi is right about some things, and it looks like the High Priest of Jupiter is right about some things too.
So, a Divine aura does indeed emanate from the altar at the cathedral, but on the other hand, if the Flambeau has sufficient Penetration he can light up the bishop.
I would interpret this as faeries can weave between the divided attention of polytheist religions. The Divine is but the result of the unified belief of monotheism. This interpretation removes the proof of God's existence and renews the need to believe. Because there's no value when there's no choice.
I should say in response, I have NO idea how the books are written and brought to market. I only sit back and read them in totally awe of the effort that goes into them and I get giddy sometimes ((mostly when reading about Tytalus and Disciple of the Worms)) when amazing stuff pops out of small little corners of cool.
So yeah I made way too many assumptions. But they were mostly jokes, I personally don't want any facet of the game changed, and certainly not because of my input. The creators of Ars to a WAY better job than I would do so my opinions would do more to detract from the greatness than add to it.
I just rail against absolutes...
To add, dear gods so MANY people on this forum are so damn brilliant and perceptive and creative and completely grok Ars Magica I am humbled every time I get a response to a thought or observation! The answers on this entire post are just.... mind opening about the world in which I often am only playing a small thoughtless fraction of the possibilities.
THat's still not every myth being true though, is it? It's every myth being verifyably false. Also, in this model all the gods who claim to be watcher gods who punish sin (which is most of the skyfathers. Not Zeus, though, who doesn't give a rats provided you still send him a cut by worshipping him.) have somehow failed to notice they are not judging anyone except their little tribe. Brahma is not laying out the wrath in downtown Berlin for all the beef eating going down, and despite being older than the earth and having omnipresence consciousness he doesn't know? That's not really Brahma, then. It's a sort of little local stick figure god claiming to be Brahma, IMO.
Possibly, although I would say it is more that the characters are wrong about the myth: the characters aren't ominiscient.
My point is that is what it is actually like in play, and that is what really matters.
"All Myths are True" and thinking that it is a problem is really a concern based on concerns about player knowledge. Characters don't know what is true and what isn't, and don't find out until Death/Judgement Day/Ragnarok/etc --- which is beyond the scope of most sagas. The characters might be able to produce evidence in play that is inconsistent with one set of myths --- but in play that just means the myth is being interpreted wrong by the characters, or the evidence itself is somehow false.
I don't think I'm actually arguing with your comments --- just expressing them differently.
For a large part, yes. But in some circumstances, it's a real challenge for a in character point of view. Think about the origin of magic (Harut & Marut, Hermès, the Nephilim, etc.)
I think our gaming group came with a solution that the original poster and you all fine people will find interesting. We tried to do with pagan deities being part of Divine instead of Feary (as is usual in the 5th Ars Magica line).
Not necessarily. Some (maybe many?) romans were syncretists. meaning they thought their gods were the same as the gods of other people. For exemple, Aphrodite/Venus is known as Isis in Egypt, Astarte in the Levant, or Ishtar in Persia, etc. Of course, each have different myths about her: but often they don't contradict, and if they do, it's impossible of the character to know the truth about it.
It's the Abrahamic religions that were the fiercest in enforcing their own religion as the only truth. For a polytheist romans, it was acceptable to have a province in the Levant where the jew believed in only one god. Some historian thinks that the hebraic religion, before the exile to Babylon, was a monolatrism - workshiping only one god, but not denying other gods exists. In some discuted version, Yaveh, the god of the mountain, have a "wife" called Ashera. After that, Judaism changed to monotheism.
Notice how the ancients, Plato for exemple, talks about "the Divinity" and the respect it seems to command from them, even if they think that the stories about gods and heros are superstitions. Notice how in hinduism, Brahma, Vishnu et Shiva are aspects of "the Divinity". Notice that, even today, many muslim will tell you how christianism is not a real monotheism: there is God, then the Son, Christ, then the holy spirit - What's that about three persons in one god!?
All in all, it become possible, with minimum changes to Ars Magica's Mythic Europe to handle the pagan deity as part of the Divine. First, the player should never be in direct contact with "the divinity" - as is supposed to be anyway. Second, you can interpret any pagan myths you wish as being true.
Our group has found a book written by Ostanes, the apprentice of Zoroastre, who - if the book say truth - has learn magic from a god. They may venture to ancient Babylon, were, maybe, they will encounter Harut and Marut. Are they Angel punished by Allah? That's what the arab sihr believe. Watchers who taught magic to humans, the one who Zoroastre knew? If they ask them, they will probably tell them to go away...
But one thing that is important for me, is to know and explain why that priestess of Aphrodite on Cyprus is not deceived by a demon on the guise of Venus. She is true with her belief and won't be converted. The Aura where their Temple is located is Divine. And it's not because Intellego spells can be deceived by demons. It's because it's really an aspect of "the divine". Those priestess do not have temple on the street, they are badly seem by the Church, but still, it's way more playable than having them be deceived by some feary lord - if you want to play "pagan"/ "Many myths are true"-way.
My post seemed to have died somewhere in the posting 
Honestly I have no idea how the books are brought into being, I only know that every knew one that comes out makes my jaw drop just a bit further in amazement. Not to tangent on brown nosing to far, I just want to add my post was not a serious criticism or suggestion in anyway. I am of the opinion that the books put out by the Ars people are simply fantastic and brilliant, I could not add anything to make them better. And while I personally rail against the concept of the Divine, I also rail against other concepts in other RPGs not because I think it is a flaw or a mistake, but simply because I have silly misotheistic tendencies.
I would not change anything about Ars... except maybe giving the Tytalus and the Order of the Worm their own adventure source book. ((This is me being flippant again... well flippant, but serious))
Yeah, not really much mythical about it. The trade with the east wasn´t mythical, and MPs tales weren´t any more mythical than a travel show on TV might be today, the only big difference being that today it´s easy to show and tell and most claims can be easily verified. I mean, all we have to do is go back a century in time to find tales of explorers that were taken as myths and makebelief(and sometimes there WAS some of that included too).
You might have a point with the above if it wasnt for a historical fact... About how people of the time didn´t have a problem with this. And that whenever possible, deities were identified cross-regionally in a "oh that´s what you call Pluto(or whichever) where you´re from" way.
I mean, if you look hard you can find deities that existed in religion from the Atlantic to the Pacific, under a dozen names.
I´m not even going to touch the "gullible" part.
That´s another decent route to go, it achieves pretty much the same as ours, merely dividing it up differently with anything that might be called a deity as part of the divine.
Yup, from what i´ve read, highly likely.
And a big +1 to that.
Sorry to bump this topic but overall how do you make Ars Magica less Eurocentric and Christian centric and have all myths/paradigms/etc equally true alltogether? Or do you have to make a entirely new game all together?
Since I do have major problem with the trend of Christian/Eurocentricism found in many supernatural settings (well the WoD included) which is a product of cultural imperialism.
You just do it by doing it. You just say "IMC, the Dominion doesn't matter much."
We have an interesting mechanic of aura's and creatures that ties in better with all myths have basis of thruth.
First, there are no infernal, faerie, or divine aura's, all is magic, but may have a flavour depending on its mythic significance. You may find, however, that bad stuff often likes Perdo, and nice things sooner are aligned with Creo.
For instance: A magic well that heals wounds may have an aura of 3, but Creo, Aquam and Corpus of 6. If a chapel is placed there, this does not change the aura to a different type, though worship may increase the aura. If the magic well is poisoned and delivers plague and death instead, it will change over time to a perdo and corpus aura.
You can only cast spells up to two magnitudes in strength per point of aura. (previous example, you may cast up to 6th magnitude spells, though a Creo or Corpus spell may reach up to 12th magnitude).
You may increase the limit by 2 magnitudes for each pawn of Vis of appropriate type you spend.
This is a blatant copy paste from what I included in the house rules thread
This was met with quite some criticism and reservation, use at your own risk.