Checks on Characteristic Improvement?

A similar issue popped up in a discussion of "what exactly is Quiet or Subtle magic, and can it be used to get around the Holy Magic penalty for words/gestures?" The general response was "Virtues are just mechanics. As such, it depends on how you define those virtues in-game. If you define them as realizing that the pagan words and gestures are unnecessary, then yes. If you define it as successfully replacing the words and gestures with appropriate Holy thoughts, then yes. If you define it as internalizing the pagan words and gestures, then no. It's up to the Troupe and the player."

So that would probably work as a similar response here. If you define a partially-integrated Hermetic virtue as already having as much of the paganism stripped out as possible, then it would work just as well as any other Major virtue. But if you define it as requiring a "pagan mindset" (or whatever), or rituals that specifically counter the ideals of Holy magic, then no - it wouldn't work.

Personally, as the RAW doesn't forbid it, I'd go with the interpretation that allows the player to do what they want.

(The other fun virtue to slip in there is the Animal Sacrifice one, from HoH:TL - that allows you to substitute an animal for vis in a summoning ritual. Which would actually fit OK with mythic Judiasm...sort of. I guess. In angel summoning? I dunno. Animal sacrifice in the Old Testament really seemed to be a way of feeding the priests, as much as anything else.)

EDIT - the reason I came up with that combo is mainly because it creates a situation in which I'd actually want to play a Mercurean as a PC - with all the penalties that it implies. Specifically, the stacking of the 1/2 cost of Vis and "you can use long-term fatigue as vis in a 3-1 ratio" is interesting enough that I'd be willing to put up with all the other stuff. The disadvantage is that the restriction on spont magic collides with the Holy magic restriction on using hermetic spells.

I'd probably add in the "quick ceremony" minor virtue from HoH:S, describe it as part of the character's Mercurean training, and call it good. (Maybe with the Cautious with Concentration virtue, as well.)

EDIT II - for example, I've always interpreted Mercurean magic as being more "structurally reinforced" than traditional Hermetic magic: the words and gestures are pronounced more cleanly, with structured foot and whole-body movements that prevent the spontaneous casting of the Diedne. But as a consequence, those gestures allow vis to more efficiently flow through the magic, and thus make rituals easier and more efficient. And because it's so structured, other magi with similar training can join in more easily.

Also, the discussions of the Bjorner magical style in HoH:MC states that their magic is no more or less compatible with the Divine than any other House.

As such, if the fluff tells us that practicing the partially-integrated hermetic magical style of a bunch of spirit-venerating/worshiping Germanic shapeshifters isn't a specific stumbling block to being a Christian/Jew/Muslim/Zoastrean, I'd say that that Mercurean magic falls into the same category.

I'm not a fan of Holy Magic myself, but if you do use it you should be aware that Renaissance thinkers had no problem at all reconciling Hermeticism with Christianity and that certain medieval Muslim thinkers even identified Hermes with the Prophet Idris/Enoch. Considering all that, legacy Order of Mercury material doesn't seem particularly out of bounds for a religious magus.

I get that you can play it fully mechanically and nothing else, but here's what I see when I read them:

Mercurian Magic: Due to the traditions (yes it says this, plus [magical] lineage) passed down from the Roman priests your ritual magic is more powerful.

Holy Magic: "holy magi cannot use Hermetic words or gestures with their magic, since they are believed to lead the magus into ingrained rites of Hermetic idolatry and invoke the symbolism of sacrilegious rituals and worldly enchantment. A holy magus instead learns to call his magic solely with the worship of God." (RoP:tD p.67)

The combination of these says to me that ArM5 at least pretty strongly implies if not actually implicitly states that the two cannot work together. Note, I'm not saying a character couldn't have both, just that they don't work together. Now RoP:tD does say holy magi sometimes regress and cast Hermetic magic but that this is believed to be sinful and doing it much could well warrant losing the ability to cast Holy Magic. Also, doing so is not Holy Magic, so it's still an either-or thing, not both Holy Magic and Mercurian Magic working simultaneously.

Sure, the Bjornaers' stuff is just as bad vis-a-vis Holy Magic as are all the other houses' magic, no worse nor better. That still doesn't change the whole thing I quoted above from RoP:tD. I accept that True Faith is fine, though justification is surely needed in-character. The issue is with Holy Magic, which is even more restrictive than True Faith.

The main thing with HM is that the fluff makes the statement that Holy Magi reject Hermetic symbology as pagan and sinful, despite evidence that it's actually not (and that Zoroastrians would laugh themselves silly at the very idea). While I wouldn't go so far as to agree that all holy magi, or even their guardian angels, are going to agree with that position, it's pretty clear that pagan symbology is incompatible with the peculiar magic that expressly draws upon the Divine and that is sanctioned for use in Divine auras. YSMV on whether this includes Mercurian Magic as a virtue, since the latter only specifies that "your lineage and magical tradition descend from the priests of the Order of Mercury." A case could be made that if you've adapted that particular tradition to run on the Divine Realm (by taking Holy Magic) and replaced pagan rituals with Christian ones (which the Church did all the time), then it should still affect your divine magic.

Yes. The Holy Magic description is quite clear as to what that restriction represents: a prohibition from using Hermetic Words/gestures (or a -10 penalty and using improvised Holy words and gestures), and a restriction from using Hermetically-derived spells. If you want to create your own spells, you have to use the Holy Magic ability, which allows you to create spells similar to Hermetic abilities, but are aligned with the Divine.

There isn't anything in there that says you can't use Mystery Cult virtues (Bjorner or Mercurean or otherwise) in your creation of new Holy Magic spells. If that were the case, that's certainly a big thing to forget to add - to the point where it really should be in the errata.

(EDIT: half the hermetic virtues in the game could probably be described as "descending from priests of X" or "descending from pagan blessing Y" - but we don't see any such restriction on them.)

Pretty much this - I see the penalties that Holy Magic puts on Hermetic magic as doing exactally this, only on the fly: ie, figuring out which saint's name to use instead of Mercury's, or to face towards Mecca instead of the rising sun, and so forth. It doesn't work as well, but the rules are explicitly there to allow you to do stuff like this.

Sure, but mechanically, it's stacking power on top of power. It means that the character is acquiring power for power's sake, and not necessarily for the Glory of God.

Take a Mercurian who knows several Characteristic boosting rituals, he has a conversion from his decidedly pagan roots (whether this is a spiritual adjustment or a magical adjustment is moot) to a more Holy, Christian, outlook. He then begins recreating all of his spells under the virtue of Holy Magic. Why? Because he can? That's not Holy, and it certainly isn't for the Glory of God. The moment one of those spells is reinvented spontaneously (without being prompted by the story or saga arc) by the Holy magus is the moment he invites the SG to start tempting him with sin and having demons and diabolists trick him into working magic on their behalf.

Qualifier - for learning the relevant virtues, I'd say it's the PLAYER acquiring power for fun's sake. In-game, it's unlikely that a Mercurean looks at the complete unintelligible mess that is Holy Magic (from a hermetic perspective, anyway) and says "yeah, I want me some of that!" Unless the PC in question actually has researched holy magic before going off and getting initiated, I'm guessing most magi get involved for more personal reasons than a hyper-efficient use of vis.

That being said, if a Mercurean DID do that, then I would agree - it would be desiring Holy Magic for a selfish reason, and they'd probably fail the Initiation ritual. Which would certainly make for an interesting story, IMO. Or alternately they'd succeed in learning Holy Magic, but fall prey to the later "you can't use it to sin" restrictions.

Sure - but that's true for any ritual spell: healing, Aegis, making a big block of silver, casting any spell above 50, etc. - not just stat improvement. The character can essentially cast any ritual at a 1:6 fatigue-to-vis ratio. That's a whole lotta vis saved. The temptation is going to be to use that for something.

However - that's a plot POINT, not a plot HOLE. Holy magi are supposed to be tempted - especially those with True Faith. In this context - their temptation is going to be greed ("the vis! Mountains and mountains of vis!") or Pride ("I can save the Order from magical exhaustion. Me! I can do it!") or something along those lines.

As such, I'm not really seeing the problem with this. Because there are, after all, completely legitimate uses for stat-boosters: Making someone healthy, or allowing them to provide for their family, etc. As such, the ability to cast them isn't in and of itself sinful - like many things, it's what you do with it. I would be totally fine with a story arc as you describe - after all, that's the reason I'd be playing such a character.

Inventing healing spells I have less of an issue, those can be used to aid the sick and the poor. If they turn out not to be used that way, then comes temptation. That starts with T and rhymes with P and that means Power.

Being a Holy Magus already invites demons to take you onto a mountain and show you all the kingdoms of the world and their glory. That's because of the path you've chosen; having any sort of Divine power essentially comes with a free Story Flaw of "demons are going to mess with you."

And I don't think that gathering power for power's sake is necessarily a sin in Ars Magica. Saying "I want to devote myself to the worship of God because God gives out cool bennies" is actually fine so long as you're not looking for True Faith, and so long as you're adhering to the tenets of your religion in doing so (which does mean avoiding falling into sin, yes). This is kind of a medieval thing; even saints are not expected to be especially selfless by modern standards, and Holy Magi's motivations are as diverse as holy magi themselves; what the latter have in common is a desire to ask God for his power and to shape their magic appropriately. (Well, that or they originally learned their magic from a Holy Magus.)

My original idea for a Holy Maga (non-Mercurian) who wanted to get her mental stats to +5 through CrMe rituals, for example, wanted to bring herself to a perfected state that could better comprehend God and His works (this was before I got TC, so her concept looked like something smack-dab between Contemplative and Monistic mysticism). Nothing unholy about that, though obviously there's plenty of opportunity for a demon to screw things up. But even more likely, as a reason for a Holy Magus to try to adapt Mercurian Magic, is for such things as healing or feeding the poor-inherently Christian things to use God's power for.