Well Cradle and Crescent has a breakthrough in it that makes it possible for magi to initiate un-Gifted with Hermetic Arts. Similar idea but the Gifted still maintain control over who can learn magic.
Nobles Parma, I'm not sure if it is described as a spell or if it's just part of the initiation ritual. Either way it is only legal because the Magi it's used on are willing participants. If it was used offensively it would definitely constitute a denial of magical power.
There is a specific (Ritual) spell described.
I'd have prefered if it was just part of the initiation, but them's the breaks.
I think your argument is very sound and I see there are great points either way.
This is why I believe that the ability to spark the Gift in mortals would make a great chapter in a book of Forbidden Magics. Either approach would generate a mixture of Threats and Opportunites for the Order. Not only does a mage have to research, develop, and refine his Breakthrough but he has to convnce the Order at large that this is a good idea.
Story ideas abound which is really what I look for in a book.
Same here. It would have made so much more sense.
Coming to the conversation a bit late but here is my contributiuon: I want something about the workings of the Order.
For example, this book would give me 'ordinary' NPC mages for the PC mages to correspond with and otherwise interact. My saga is quite simulationist so the 6 PC mages tend to have different interests and objectives. They want to interact with other mages who share these rather than with their 5 fellow covenant members for once. As a storyguide I find this time consuming and a challenge to make these correspondents unique. A book that provided some help with this would be great.
As some details of "ordinary" mages would not fill a whole book, other aspects of the working of the Order would be included: something on the Grand Tribunal, perhaps some history, something on the circulation/travel of Hermetic mages, perhaps on the traditional rivalries and alliances between tribunals.
In short, a book that fills in the workings of the Order to help the Storyguide simulate a great organisation working 'behind the scenes' of the covenant that is the story focus.
Those books are called Tribunal Books - I'd say Guardians of the Rhine (just for example) has a lot of the stuff you're looking for. 
What I would not mind seeing (either as a dead-tree or as a .pdf) is a greatly expanded version of the Mundane Beasts download. There's only, what, a dozen or so animals there, and I'm having to flip back and forth between my 4e The Medieval Bestiary, the Houses of Hermes: Mystery Cults, and sometimes Realms of Power: Magic if I need anything beyond its Characteristics and Size.
I'd seriously consider picking-up a pdf version of a new Beasts book, but would struggle to justify the paper version cost as I have the 4th and 3rd ed versions and the 5e Mundane Beasts download.
I'd certainly love more of the Hermetic projects material, and very keen to see every tribunal detailed. The Islam book was not at all relevant to my game, but was a fantastic book imho.
I think this would be good, but maybe more so as a PDF... We did consider the option of a Web only appendix PDF for Cradle and the Crescent when we were having word count issues but I think it worked better that we were able to roll back the supernatural creatures into the book as well as keep most of the mundane creatures. I still have a lot of mundane beasts left over - enough to fill another PDF in any rate or an extended Sub Rosa article if I don't find a way of dropping them into upcoming supplements.
Supernatural creatures need to be scaled for magi power levels but mundane creatures provide good basic opponents for grogs / companions and ideas for Heartbeasts / shapeshifters.
The problem is that a book of creatures in Ars terms is well, a bit boring to be honest and as ironboundtome notes we already have the ArM4 Revised Bestiary.
A book of creatures with Story seeds, an index of all the rules scattered throughout the supplements or even just a reprint of all the relevant rules for creating / training etc mundane animals would be more useful IMO. Add in some Beast specific spells, some Mystery cult ideas etc etc and you'd have something much more than just a critter per page style splatbook.
Sort of like Magi of Hermes but with err, Beasts. Ahem. Beasts of Hermes anyone?
Cheers,
Lachie
Even having a compilation of rules for making creatures in one convenient location would be a bonus, perhaps as a .pdf download if nothing else.. I tried making my first Familiar last month, and after three days of flipping back and forth between HoH: MC, Realms of Power: Magic, and the 4th ed The Medieval Bestiary, I finally threw my hands up and decided that, since it was an npc magus's Familiar I could just hand-wave it. But, still, I would like to know how to make a familiar in case I ever play a non-Bjornaer who gets a familiar and have to build it myself.
FORBIDDEN PLACES
A sequel to the earlier book on Forbidden Magics is a book on locations that various Tribunals have forbidden
Magi to approach.
Each chapter could be a place that apprentices whisper about. Places of Danger or Dark Magiks!
An abandoned covenant where Tytalus magi practiced and perfected their infernal rituals.
A diedne covenant. A particularly important one. One the Roman Houses want every one to stay away from.
A prison for a powerful demon, ghost, faerie king
A Regio where the evil fae Queen of Winter is trapped.
A warehouse full of infernal books, materials, and enchanted items are stored for the Order.
A cave inside of which is stored a book. A Questentar book full of all secrets that decades of investigation have uncovered. Crimes covered up, research stolen, murder and many other crimes. It was collated by the House to serve as blackmail material in the eventnthere was a concerted effort by the Tribunals to remove the Quaesentars of their authority.
A castle that stores the sleeping form of King Arthur, or the rightful king of France, or the Blood line of Christ, or Achillies, or whatever
A Criamon labyrinth of such cunning complexity it has taken on a life of it's own. And it had the Gift!
A meeting place of the Arch magi. where the Secret Mystery cult known only to the Arch magi is based. What terrible powers does it conceal?
Basically the whole book will be a bunch of fleshed out story ideas. There could be a lead or two to track down first. Difficulties in approaching the Location. Avoiding those who wish to protect the secret. The awful thing nside. And some art of twist. I imagine each chapter being a bit like the Broken Covenant of Calabais in structure.
While these Locations are Forbidden for Magi to Approach or even think about, I would assume that they would act as a sort of waving red flag tp Pc's
Count me in.
-Ben.
Inspired by some ideas brought up in this thread. [url]https://forum.atlas-games.com/t/join-or-die-ooppsie-hermetic-code-issue/6924/1]
DAWN OF HERMES
A source book about Pre-Hermetic magic and the early order. Usfull for running sagas set earlier in the games timeline as well as bringing archaic magic into a 1220 setting.
Chapters could include.
A chapter on Mercurian Magic comparable to the treatments of Hedge and Rival traditions in other source books.
Similar (Though possibly less in depth) overviews of the magic of the non-Latinate founders.
The much asked for but challenging to do Deidne write-up. (By focasing on the historical pre-hermetic pre-pre-schism version it might just be doable.)
A chapter on partial hermetic wizards. Practitioners who's magic has the same basis as the Order's but for one reason or another they lack the full capabilities of a modern hermetic wizard.
I like this one, though, I would prefer not to see a write-up on Diedne just to keep it all so mysterious.
-K!
I also think this looks very cool.
I think that you might also require a chapter on how the mundane setting is different. I understand that ariculture, trade and social structures changed significantly in the period between 900 AD and the default setting of 1200 AD. Feel free to correct me if I am wrong but during this period there was a real danger that Islam was going to sweep over Europe.
First, thanks for the compliments 
I agree you'd need a lot more information to actually run a saga set in the past. It may be a little to much to ask for in one book. It almost amounts to an entirely new setting. Perhaps the Idea could be adapted to something more relevant to the 1220 setting. Keep it focused on the building blocks of the order and what "Modern" magi could learn from them. Remnants that might hold forgotten knowledge or secret threat. Call it.
LOST MAGIC or RELICS OF HERMES
Keep the write-ups on Mercurian magic.
Deidne is a struggle but a chapter of sugestions with perhaps two or three possible interpretations might work.
I’d be interested in a book about the hermetic frontier. I realize there’s been a lot of “outside the order” stuff lately and some people aren’t fans, but I think this would be an interesting topic.
Jutland and Sjaelland: Apparently it’s up in the air whether this is unclaimed or part of the Novgorod tribunal – and either way the Rhine tribunal has their eyes on it.
Iceland (and Greenland?): I’m guessing these are already covered in Ultima Thule, but I figured I’d throw them out there.
Maghreb: Not the entirety, but focused on a few areas ripe for Hermetic colonization and exploration: Tunis/Carthage, the Pillars of Hercules, perhaps a jaunt into the Atlas mountains.
Ethiopia: A little farther afield, but I think it has a lot of opportunities and the fact that it’s Christian adds diversity. (And you can’t go wrong with Axum ruins.)
Sultanate of Rum: I don’t have Blood and Sand, but I believe this is largely outside the Levant and Thebe tribunals, and is also on the periphery of the territory details in The Cradle and the Crescent.
Canary Islands: According to Rival Magic these are featured in Ancient Magic, but I don’t know how extensively.
The two big problems I see with this is, “would it rely too much on existing books” and “are their authors interested in these areas.” Denmark has a lot going for it, but do you assume people have access to Hedge Magic and Rival Magic? Same with Rum (and possible the Maghreb) and C&C. As for the other issue, I know I’ve mentioned Ethiopia before and I think it would make for a great location, but that doesn’t mean there is something with the background to write it. 
Still if this is a thread about wishful thinking there’s something thinking which is wishful.
I like it!
The main problem with Denmark (and indeed the rest of Scandinavia) as I see it, is that the glory days were over by 1220.
No really, obviously, but everyone would be expecting to see vikings, but those are about a century out of date by 1220.
Denmark by then was a christian feudalized (or feudalizing) medieval nation.
Would you want to be the author that disappointed so many silly hopes?
Sweden and Norway might be slightly behind, but I wouldn't expect too much - I'd have to leae it to others to say for sure.
The Thebe tribunal managed to contain a lot of Classical Greek mythology despite it being even more out of date. While the mundane elements of Denmark may lack a viking flare, I suspect the mythic elements and native magical traditions could make up for it.
Denmark is tricky on the topic of hermetic colonization and exploration since there's already a good example in Guardians of the Forests. I suppose it could be expanded upon, but it sort of adds to the problem of "if you want to understand the chapter you better have all of these other books!"
But without Scandinavia my frontier choices are all to the south (I assume pushing eastward would land you in the middle of some unhappy Mongols, not the best place to set up a frontier covenant!).