Arguably, all the immortality mysteries break the Limit of Essential Nature.
Whenever I read that the Parma is the only known Hermetic Breakthrough, I always think the Order must be unaware of The Greater Elixer or Ascendancy to the Hall of Heroes.
Hi,
Unless they all kill the celebrant and leave Something Else in his place. The suicide ghost mystery is blatant about this.
(The Criamon mysteries do seem to qualify)
Mythic Alchemy allows for true transformation (not merely improvement or weakening) of matter, which violates Essential Nature.
And no, Solomonic Magic doesn't break Greater Limits. It breaks two Lesser Limits, fhough: Aging (through Al-Iksir, which does allow true reduction of age) and Energy (that limit is not present in Solomonic magic). It also bends the Limit of Creation - specifically, allowing magic to make permanent alterations to qualities of matter (that do not violate Essential Nature) without vis, Finesse or material components.
Hmm. I need to review that more closely. I left with the impression that it stayed just within bounds, or that alchemy was not quite magic, but maybe I just didn't pay close enough attention.
It sort of allows true reduction of age, but not fully: It does not unwind Decrepitude and does not unwind the need to make aging rolls.
Anyway,
Ken
Mythic Alchemy is pretty clearly magic, not Experimental Philosophy. It's a Supernatural Ability, and its placement in the Magic Realm is further confirmed on TC&TC 91 (where it discusses a Divine version).
The reason that it exists is that there ought to be a way for alchemists to turn lead into gold somehow - the Lapis Maior is essentially an alchemist's masterwork. But it does break Essential Nature - I'm okay with this, as breaking Essential Nature (both to turn lead into gold and to become immortal - which have much the same connotations) is kind of the point of alchemy as a discipline.
Reducing Age alone breaks both the wording of the Limit ("halt or reverse natural aging") and the spirit; while a sahir cannot remove Decrepitude, he can prevent himself from ever getting any in the first place if he takes an Al-Iksir every twenty years. (Where'd the guy who was proving this go, anyway? 
)
That's the one. He stopped the experiment before it ran its course.
Anyway, the idea that immortal sahirs are not difficult to get even without heavy optimization stands, so Limit of Aging is broken.
It's confusing because the same alchemists use both "chemical" alchemy and "mythic" alchemy. The chemical one is akin to Rego and the mythic one is akin to permanent Muto, and requires vis.
Transforming lead to gold feels much more appropriate than creating gold ex nihilo ala Hermetic Magic.
I suspect that the Order of Hermes misunderstands the Limit of Essential Nature and that it will eventually be found to read something like the Limit of Creation, prohibiting permanent effects without the use of raw vis.
Ahemm. I really really want to go back to that one.
It's just that the project came under some severe criticism for its "experimental" premises and some rules interpretations that I decided I had to restart it from scratch. But I'll get back to it!
When I was writing the rules for Al-Iksir, I intended to walk right up to the Limit of Aging but not actually break it-- I thought the wizards who represent the setting's best alchemists and physicians should have a fantastic longevity potion that feels very different from the Order's, and is arguably better than theirs. They are manufacturing and drinking a poor copy of the Water of Life, and so the things it does to the body should feel suitably miraculous.
Mechanically, I decided to interpret the phrase "natural aging" as referring to Decrepitude as far as the Limit of Aging goes. Sahirs can't halt or reverse the accumulation of experience points in their Decrepitude scores, which is what will eventually cause them to die of old age. The character's numerical age only affects the outcome of the Aging roll, but it's the Aging Points and their effect on Decrepitude that represent "natural aging."
As far as the spirit of the Limit goes, it is well-established that different traditions can trade longevity for other negative effects. Hermetic magi don't typically die from aging, they effectively die from Warping. Al-Iksir too has a cost; the penalties that sahirs trade for Al-Iksir are interesting, and certainly more severe than just gaining Warping Points. I think a sahir who drinks Al-Iksir continually to keep his mortal body young will soon go mad in one way or another-- and players can use that to make really interesting stories for the other characters in the saga, I imagine. 
(Old sahirs turn into antagonists, I think.)
Yes, the sahirs do break the Limit of Energy, but that felt like kind of a letdown because it's just copying with Solomonic magic what mundane medicine can do.
Regarding the original post, I think it's a clever idea to use Algiz with Dagaz. It could be argued that this would ward away light as well as time passing. I might be willing to allow it in a game I ran, but I would probably attach some rider to it, like that when the rune is broken the vitki must make all the rolls that have been put off. So basically it would be a time bomb to use when death from old age seems imminent. Or suppose it effectively put the vitki in Twilight, invisible and unable to affect the world for the duration but also not affected by it-- also kind of cool from a "ward away the light of day" standpoint. How adventurous is this hypothetical vitki?
Fair enough. I personally consider it a broken Limit because you can ultimately get a 400-year-old ashir with limited drawbacks, but I'm okay with Solomonic Magic breaking multiple limits - it's the most developed Rival Magic out there and the widest-practiced by far. And either way, I'm rather splitting hairs. 
Now you're selling it short. Solomonic versions of Experimental Philosophy can do, either in seconds or in an hour or so, something that would take seasons of work to do as an experimental philosopher, and with the aid of either a spirit or simply the Art, can do things that they wouldn't be able to comprehend a Lab Text for. In particular, even weak sahirs with Physic can easily wipe away short-term fatigue at no cost, and while this doesn't break the game like wiping long-term fatigue for free would (Solomonic integration of Hyperborean Hymns? 
), it's something that magi who weren't completely in the grip of Not Made Here would kill to have.
Pretty sure that was accidental. Anyway they don't actually halt aging. Mechanically they always have a chance of getting more decrepitude, but as long as they keep studying the chance drops so fast they might never die. Less mechanically you would probably describe it as the age increasingly slowing down. Never stopping, but never getting to the end. First you age at half rate for a decade. Then 25% rate for a decade. Then 12.5% rate for a decade. Etc. No matter how many decades pass you'll never age a full decade. And if the Sahir had 12 years left when this started well...
Edit: Yeah, I was right about it not being intentional
Theorycraft being all well and good, but a Sahir is a mortal and can be killed, and those that deal in magic lead lives with significant danger. Can live forever isn't really a problem in any game setting, even one where time passes quickly like Ars Magica.
It might lead to the issue of "So where are all the immortal Sahirs?", but the easy answer is kind of built in; they died of injuries or went nuts.
Well, I don't think anyone was talking balance, so much as talking whether sahirs broke the Limit of Aging. Which I contend they do, but I also understand the rationale behind the argument that they don't (if the march of Decrepitude is seen as the true Limit).
And this is the Ars Magica forum. Theorycraft about arcane technicalities of the game's magic system is at least half of what we do here. You're right that a sahir is ultimately going to suffer death by life, of course. Whether Al-Iksir actually breaks the Limits is the kind of thing that would be more interesting to Seekers, since sahirs generally don't look at their magic in quite so systematic a way. "This ability breaks the Limit of Aging, let's integrate it into Hermetic practice for the Bonisagus equivalent of penis length." "No, it doesn't break the Limit, it just does a dance around it and has some ugly side effects too. Let's go look at their Energy magic instead."
So far, only Criamon break the age limit. And I think it fair to say that they do break it.
Merinita do too. And I'm not talking about Becoming, but about Guardian of Nature: "As a guardian spirit, the maga does not age". Note that the maga may leave this state at any time, so it can't be argued that she dies and leaves something else in her stead.
Hi,
Agreed, Guardian of Nature too. Even though iirc, they get 1 wp/year for the privilege. Criamon just have to be Criamon.
Anyway,
Ken
And, of course, immortality Mysteries also break the Limit.
While we're looking at uses and abuses of Algiz warding, here's two examples from my blog at magioftom.wordpress.com/2015/11 ... ng-olunar/ that I am considering adding to the Non-hermetic grimoire:
I, (the runemaster), defy Gullveig - Algiz(perth) 10, - wards against hostile magic. Algiz base 10 wards all things appropriate to the secondary rune, and according to HMRE p135 "Often Perth is used to affect the supernatural realms, particularly magic. It can target vis, and can also target other spells and supernatural effects".
I, (the runemaster), defy Surtur - Algiz(Kauno) 10, - wards against fire, heat, and feverish diseases. Algiz base 10 wards all things appropriate to the secondary rune, and looking at Kauno on HMRE p132 it includes all these things.
Now the second one is relatively straightforward. The first one - how would you adjudicate the warding? Does it competely ward against all spells (so you can't use your own beneficial ones) and prevent you picking up vis, or should it not completely ward?
If it shouldn't ward completely, would a more appropriate effect be the Perth guideline "All supernatural effects cast on the target that are less than or equal to half this effect's level are dispelled" so a level 10 would ward against level 5 hermetic spells and supernatural abilities with a score of 1 being used and scale up by a magnitude per extra 10 levels of Perth magic applied?
The Limit of Essential Nature, not the Limit of Aging. Once you've got Might, aging isn't a thing anymore (unless you have the right Flaw).