Well, I'm pretty sure the Verditius Magic would be a major virtue without it. I do agree, Verditius Magic is probably worth more than a minor, even with the flaw, but the principle stands 
Did I mention that Sub Rosa issue 13 is a House Diedne special?
Major virtues don't become minor because of the flaws associated with them. Were that the case Mercurian Magic would be a minor virtue!
I can't be certain why all the MCs have minor virtues as their House virtues, except of course, all Houses have minors as their House virtues, and so I suppose it was that sense of "balance." But on its face, I don't consider casting tools a "flaw." I don't often, in fact I have never, taken them away from someone. I can reasonably assume a character will keep his casting tools and the grog who carries them in his pack close at hand, or he keeps said tools on his person. If, as Spontaneous Casting Tools from HoH:Societatas suggests, that there are 15 necessary tools, one for each Art, having them on a necklace isn't impossible.
It depends on how powerful it is before you add the flaw. Sometimes the flaw would just move them from "Impossibly powerful virtue" to "major virtue". I'm not sure how well balanced the system actually is, but that seems to be the principle at work.
There are many reasonable situations in which that might not be sufficient. Someone with a low level Perdo X spell could destroy them. A paranoid individual might make you leave them behind. etc.
Sure, they're not a flaw if you're running and choose not to make them one, but they're clearly intended to be a flaw. They're akin to a necessary condition.
The impression I get is that those 15 are only for spontaneous. Each individual formulaic spell gets a casting tool. If there's just 15, Enchanted Casting Tools doesn't really seem to work.
I don't consider Mercurian to be all that powerful under RAW. Can't use it to cast the Aegis, because you need a Communion which negates the major benefit of having a Mercurian cast it, unless all the participants are Mercurian, and how often does that happen? And then just how often are you casting rituals anyway? Really?
And I had this discussion elsewhere and I left out Verditius, so did the other part[y/ies], when discussing virtues that have built in flaws, or required flaws. Diedne is the only virtue that has a built in flaw that is a major one, counts for 0 points in Flaws, and essentially prevents a player from taking another story flaw, since, as a rule, players should only have one. Of course should is <> must.
Sure they are, but in reality, Necessary conditions and Restrictions are relatively easy to work around. Not all Virtues and Flaws are created equal. Magic Addiction, for example is a much more potent Flaw than either Necessary Condition or Restriction, because it affects nearly every spell, all nearly the time[1], and there's always the chance for botching. Blatant Gift may or may not be bad, depending on how well a troupe actually RPs the Gift. Rigid Magic and Unstructured Caster are both pretty powerful flaws, all but precluding a class of spells for each group. This is one reason why the concept is important, why the discussion of story, and how the saga is going to work, so that the player can play a character that's going to be fun. In a high adventure combat heavy saga, is Slow Caster a minor or a Major virtue?
I can go either way on that interpretation. If you need casting tools for spontaneous spells, representing every Art, why not casting tools for every Art applying to formulaic spells. Unless, and I might have missed it, each spell has its own unique casting tool. Even still, this is where a Verditius will rely upon his Wand of PoF or other suitable destructive combat spell enchanted into an item, than relying upon vagaries formulaic magic.
[1] The decision of what is a stress die is largely in the hands of an SG. And even the RAW can really mess with someone with this flaw. Take a spell like the Leap of Homecoming, a 35th level spell, cast it under stress, with a magus who can barely cast it, either due to requisites or just raw ReCo CS and arriving naked, his EF to check for continuing to cast is either 17 or 18, probably 18. So he's almost always going to be casting spells until he can gain control, which might be a couple of rounds,and he might be 1 or 4 fatigue levels down.
Edit: added nearly to the description of when Magic Addiction applies, and the footnote.
Just to clarify - What I am aiming for, is a description of House Diedne PRIOR to the Schism War.
If I can get a plausible impression of the House pre Schism - then I can continue to consider the implications for any "survivors" in the "present day" (1220 
)
- some Diedne may indeed be hiding in plain sight. And one of the implications of the "Oral Tradition" flaw is that it need not be overt. If you were a lone surviving Diedne you could fit into a another house without gaining the attention of Quasitores or the Vexillation of the Burning Acorn... You might get a reputation for being a somewhat slow learner though... but that is neither a high nor a low crime in the Order...
That is a quite an interesting observation. I allwas had the impression that according to Hermetic history the Diedne were not fully integrated...
Well, there is nothing canonical about House Diedne, except what has been written in the ArM5 book. So, any opinions are likely to vary wildly.
My question is why are you trying to do get an idea of what the House was like before the schism? What problem will it solve for you, that you currently have? Again, repeating my comment above, without answering those questions you're going to get a lot of different opinions.
There has been a bit about the Diedne spread around the supplements in this edition. Here's a thread from 2007 that gathers a good number of the statements about the house together
@Jonathan:
Well, its not so much about solving a problem... Its more about exploring the magical lineage of celtic magic - starting with pre-Diedne Druidism and ending with any surviving members of that lineage today.
- what would be the defining characteristics of such a non-roman lineage?
- what were their role in Celtic society and how does that reflect in their magic?
- what would change as the magical tradition got involved with the Order?
- what would change after the Schism war?
- what could endure over time?
Of course I could have started with questions of balance and gameplay and then working backwards in time from there...
... but I must admit that I really enjoy this exercise into fictitional magical genealogy...
EDIT:
@Erik: Thanks for that link - very interesting argument unfolding in that thread
@Mark: Ill be looking forward to the 13th Subrosa then 
I've only skimmed that, but, as best I can tell, it doesn't address any of the mechanical issues related to how the House functioned. So, I was imprecise, but the gist was correct, in that I was referencing mechanics, which is what John the Arms was looking for.
So,
Your Diedne May Differ....
For me, their pinnacle Inner Mystery is Controlled Metempsychosis. The Druids believed that everyone reincarnates. A mature Diedne has mastered that process. You can kill him, but he'll just come back as someone else, remembering everything. The character even has quite a bit of choice in who. Just because Tremere are paranoid doesn't mean the Diedne aren't out there, with a good memory of everything, including the true value of Guernican honesty.
A critical Diedne Mystery is the ability to keep a secret no matter what. Otherwise, it would have been too easy to capture one of them, wait for Parma to go down, and InMe all the Diedne secrets. Especially if you have one of them imprisoned, say, at Magvillus. This would be the gateway Diedne Mystery. A Diedne's mind is inviolable, immune to any InMe, ReMe, PeMe or similar effect. As a flaw, he also cannot choose to reveal a secret he has agreed to keep. This perfection of mind might include an inability to forget. Such inviolability might appear similar to that of demons...
Between these, you can have what you like. Human sacrifice instead of vis? Something foresty for those D&D druids? Casting parameters for curse-like or blessing-like spells?
Anyway,
Ken
And that is definitively a cool idea 
For human sacrifice, go for Chtonic Magic and you have all the bad stuff you want there without the need for demons to intervene.
That is mindblowingly awesome...
stunned*
This is a really interesting thread. I found this link a couple of weeks ago when I was doing a bit of random research on the Diedne. Its Matt Ryan's Blog and has some interesting perspectives on the house that shall not be named.
Hi,
Late to the thread due to forum issues, but I would like to raise a dissenting voice to the opinion that House Diedne was a Mystery Cult. I don't deny that it was a very secretive cult, but given its sheer numbers -- it was the largest house at the time of the Schism (HoH:TL, page 40) -- then a Societas seems far more likely. I imagine when the (probably Gaulish) Diedne joined the Order she recruited her own tradition, but also druid-like traditions from all over Mythic Europe. This promoted rapid growth, allowing them to be so big so soon. Since there was no pan-European 'Celtic' culture (that's just a convenient label for historians), all of the recruited druids would have a different religion and different practices -- this in itself makes a Mystery Cult difficult. For a Mystery Cult to work, Diedne would have demanded that druidic priests abandoned their religion in favour of her own brand of idolatry. In a Societas, everyone could be free to worship how they will. I see House Diedne as being much like House Ex Miscellanea but with better leadership: lots of individual sects ruled by a council. It may be that what is known in 1220 as Diedne Magic might just be the magic of one type of druidry, perhaps the Gaulish branch. That Virtue may not have been shared by the whole house; each sect might have had its own Major Virtue, Major Flaw, and Minor Virtue, for example.
There is no doubt that religion was a big part of House Diedne. However, I also disagree that Pagan was an obligatory (or even a common) Flaw. This is a Story Flaw -- you don't take it if you want your character to be pagan, you take it if you want to have stories about your character being pagan. If you have the Flaw, then you won't simply keep your faith quiet like other secret pagans; you bless the Goddess out loud, you openly wear a symbol of your faith, or someone knows your allegiance and persecutes you because of it. Further, it is an exceptionally bad idea to force every player of a (living) house to take a Story Flaw (let alone the same Story Flaw). Each character can only have one Story Flaw, and this basically makes Diedne the 'cookie cutter' house. It is not the same as having all members of the dead house take Dark Secret; by taking the Diedne Magic Virtue in the post-Schism world you are deciding to play a particular type of character.
Mark
To Mark:
True that the Diedne numbers make them more probably one Societates centered about Spontaneus, some Mystic approach and related Ethnicity, but i don't see so far difficult the Mystery Cult. Truely the Pagan Flaw ithik taht should be rare, but on another side Cabal Legacy or related minor flaws could be very common (Vow, and so on), very related to the practices. And another thing, Celtic related people were not only on the now France and the Brittish Isles. The Celtics were on Germany, Poland, Iberia, Italian ¡until Greek zone!, and i know that the Celtiberian and Celtic lore still on many historycal and language theme. So, i think taht if not relligiously mayble folklore and language could link them.
Hi,
The problem is that they do not act like a society us. Yes, they are presented as large, but also as organized, with a common culture. Worse, the fifth edition presents them as being local rather than scattered across Europe. If we assume that the Druids went underground, then the Edney did not need to create a mystery and recruit a large body of people to agree with it and change their ways, but only needed to reach out to the existing network and convince them to add hermetic magic to their tradition.
Yes, by hermetic standards they are large, but bytheirstandardsthey are a lot smaller than they used to be before Caesar came…
Also, by their standards hermetic magic was Probably considered an improvement added to the main body of what they already had, rather than what they already had being an eccentric twist on Hermetic Magic.
Anyway,
Ken
+1 to Ovarwa's post.
Not much more to say atm.
I get no such indication from what little there is on House Diedne. I have in the past combed through the Fifth Ed sources and collected quotes on what we do know; I'll see if I can dig this up.
My point is that whereas today we know that the various 'Celtic' people share a common origin, A) I very much doubt that they saw it that way; and B) these cultures were barely extant in the eighth century when the Order formed. It seems unlikely to me that the druids of all these disparate relic populations scattered from Spain to Ireland to Poland to the Balkans had any contact with one another, or that they still shared religo-magical practices after thousands of years of separation.
If Diedne inducted them all into a Mystery Cult, then they would have had to conform to her sect's religious and magical beliefs*, enacting her own "Join or Die" campaign. That's just another form of religious persecution, something that these pagans probably know a lot about. The Romans tried the whole "You can carry on worshipping Ogmios, but you have to call him Hercules" schtick, and look what happened.
*unless she created a syncretic cult from scratch. You've just got to look at Wiccanism to realise what a bad idea it is to design a religion by committee.
My point behind these posts is to provide an alternate view. The version of House Diedne I'm suggesting here would be a societas made of many sects, each a mystery cult. Each sect has its origin in one of the pagan groups that Diedne encouraged to sign up to the Order. Each would have their own Mysteries that are distinct from the others; the commonality is that they are all diehard pagan remnants. There may have been a core of the house which represented Diedne's own tradition. Any pagan sects -- whether 'Celtic' or not -- could have joined; leaving Ex Miscellanea for the non-religious magical groups, plus those religious ones with history of hatred of House Diedne (like the gruagachan). After the Schism War, some of the sects may have joined Ex Misc after renouncing their Diedne past.
When it comes down to it, we know very little about House Diedne and its practices. Since it seems unlikely there will be an official version of the house, each troupe has the freedom to come up with something that satisfies them.
Mark
Yeah, on your thought you are very clear and you are right (specially on the last phrase), Diednes can be anything taht any Game/Chronicle/Group/Storyteller needs, that is the correct way.
I think again that the identity on Celtics can be not the same, at least with their near commoun Language and Society to have links through Europe, specially on Mytich Europe. The historically merchant routes that explain som materials on Ancient Celtics places argue at least on that way. But of course not all Original Celtic wizards or priests can be thought be Diedne or become part of the Order in that way.