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Fourth to Fifth

The Fifth Edition Web page has some design notes from the author of Fifth Edition (see the "Downloads" box in the right-hand column on that page). They explain several design changes between Fourth and Fifth Edition, in more detail than this FAQ.

The Big Picture

The Appendix to Fifth Edition probably says it best: there are two viable answers to the question of what is different between Fourth and Fifth Editions. The first is "nothing has changed." The second is "everything has changed."

"Nothing has changed" in that, if one had to describe Fifth Edition in 500 words or less, that description would be unchanged between editions.

"Everything has changed" in that almost all of the rules have received some revision. Just about every line or box on a character sheet has been affected by the changes, and probably every page of ArM5 rules has mechanical differences from the ArM4 rule.

Detailed discussion of the changes will proceed chapter-by-chapter. Even the chapter structure has changed between Fourth and Fifth Editions; I will follow the structure of the Fourth Edition book on the assumption that the people most interested in this question have seen Fourth Edition, but not Fifth. (Fourth Edition is available as a free download.)


The story about Antoninus of Jerbiton has been replaced with a much shorter introductory piece.

There are no quality dice in ArM5, only stress dice and simple dice. It is possible in ArM5 to have a stress die with zero botch dice, and this is what is used on the rare occasions when a quality die was called for in ArM4.


One set of design notes covers the Fifth Edition character creation process.

Characters are still constructed the same way; a concept, followed by Virtues and Flaws, Characteristics, Abilities, Arts, and spells.

There's no dice-rolling method for creating characters in Fifth Edition; point-based buy of Characteristics is the only option, though new Virtues and Flaws can increase or decrease the number of points available.

Abilities (skills) and Arts (magic) are now drawn from the same pool of points, both at character-creation time and as experineced PC's advance (though advancement points are usually specific to the source of learning). Abilities cost five times as much as Arts. Magi now have more flexibility in how they allocate points between Abilities and Arts.

The ArM5 template characters (once the errata are included) are completely legal - unlike the ArM4 templates. These may be useful to new players and/or SG's.

Houses are now split into three kinds: "True Lineages" (which are the same as in ArM4), consisting of Bonisagus, Guernicus, Mercere, and Tremere; "Mystery Cults" (as per ArM4's "The Mysteries"), consisting of Bjornaer, Criamon, Merinita, & Verditius; "Societas" (groups of like-minded magi), consisting of Flambeau, Jerbiton, Ex Miscellanea, and Tytalus. Each kind of House is getting a separate "Houses of Hermes" book.

Probably the biggest difference is in Virtues and Flaws. Each Virtue or Flaw has been changed to have only one of two costs - Major or Minor, at 3 or 1 point, respectively. Magi and Companions are still built on up to 10 points, and Grogs on up to 3 points. Grogs may only have Minor Virtues or Flaws.

Two new categories of Virtues and Flaws are introduced in ArM5 - Personality Flaws and Story Flaws. Characters are limited to two personality Flaws and at most one Story Flaw; grogs may not have Story Flaws at all. Story Flaws are explained in the design notes.

Some former Virtues are now Flaws. The key factor in seemingly-advantageous "Flaws" (such as the former Virtues) is that each represents a story hook the PC *must* take if it's presented by the SG (e.g. your Faerie Friend has been summoned to Arcadia, and your PC MUST deal with that, either resisting the summons or going with), rather than a bought-at-creation advantage the SG should leave intact.

Hermetic Magic

The big change is in how Penetration works. Penetration in ArM5 is calculated as (casting total + bonuses - spell level), meaning that one has a higher Penetration with low-level spells than with high-level spells. The effect of this is to greatly strengthen Magic Resistance, including Parma Magica. It also helps make the game challenging for experienced magi, who may be able to cast high-level spells, but will still have low Penetration with them.

There are new rules about how having an Arcane Connection to the target can improve one's Penetration.

The scope of the individual Arts has been changed, causing some spells to change Arts.

Magi in Fifth Edition gain a generalized "Form Bonus" equal to (Art / 5). This bonus applies to Soak totals and other rolls to resist attacks from that Form. This rule was not present in Fourth Edition but it is similar to something that existed in earlier editions.

The Limits of Hermetic Magic are explained in more detail and, some would say, more clearly.

The social effects of the Gift are explained differently in Fifth Edition than in Fourth.

It is no longer possible in ArM5 to use vis to extend the range, duration, or target of a spell. Spells with permanent effects, such as a spell that permanently heals a wound, must be rituals. However, a new kind of healing magic has been introduced: spells that grant a bonus to wound recovery rolls while they are in effect.

Spontaneous spells always use a stress die in ArM5 if the caster exerts himself (spends Fatigue). Non-exerting spontaneous spells do not involve a die roll at all any more. It is possible to get a bonus to spontaneous spells through "ceremonial casting," which is a slow process kind of like a ritual, but without the need for vis.

In ArM5, most spells, including Pilum of Fire, automatically hit their targets. The only spells that require an aiming roll (the ArM5 term for what was once called a "targeting roll") are spells that affect their targets indirectly, for example, by opening a pit under a person's feet so he falls in.

Magic resistance works a little differently in ArM5 than it did in previous editions. In a nutshell, magic resistance categorically keeps out magic, including enchanted objects (flaming swords and the like). Magic resistance remains a controversial topic of discussion online, but (unlike past editions) most of the controversy is not over how the rules are supposed to work: it's about the so-called "Pink Dot Loophole" and house rules that might resolve it.

Spell mastery now relies on Abilities (skills), each representing mastery of one spell. When a magus attains a new level in a mastery ability for a given spell, he gets to choose a special trick or power (like multi-casting or getting a bonus to cast without words) for that particular spell.

ArM4-style spell foci, which were little props that gave a bonus to the casting roll, have been dropped from the ArM5 basic rules.

Casting from a text is not mentioned in the ArM5 basic rules.

Certamen has been rewritten in both mechanical and legal terms. There is no specific Certamen skill any more. The certamen rules more strongly parallel the regular combat system. The social conventions surrounding certamen have been revised to make it harder to abuse certamen to bully weaker magi, and the method for choosing the Arts involved has been changed to make narrowly-specialized magi less dominant in certamen. On the other hand, many more Certamen options are now given in the Tremere section of Houses of Hermes: True Lineages.


There are design notes describing the changes in the laboratory rules. We have nothing to add to what is said there.


Some significant changes here. First, as has been mentioned already, formulaic spells can no longer be boosted with vis. If you want the spell to last a year, in ArM5 you have to design it to last a year, meaning it must be a ritual.

There are no permanent spells in ArM5. The ways to work around that are to use an enchanted item (with a continuous effect) instead, or to design Ring/Circle spells and cast them on a circle that is carved in stone (those would be "almost" permanent).

The range categories for spells have been changed. Spells can be either Personal (caster only), Touch, Voice, Sight, or Arcane Connection. There is no longer any such category as Near or Far. The Voice category is generally a replacement for Near, and takes a little getting used to. A Voice-range spell extends as far as the caster's voice can be heard, which can be a long way if he is yodeling from a mountaintop or a very short distance if he is whispering in a hurricane. Spells that work well when cast silently should be Touch or Sight range; a Voice-range spell cast with no voice at all can only affect the caster - even if the caster has the "Silent Magic" Virtue.

The there is a set of design notes describing the changes to the spell rules in more detail.


As is traditional, the combat rules have been rewritten from scratch with the new edition. The designer's notes discuss the changes in broad detail.

One key difference is that "trained groups" now have a big advantage over a mob of individuals; for comparably-skilled combatants, a trained has an overwhelming advantage.

ArM5 does not use "Body Levels" to track wounds. Instead, wounds are recorded individually and each has its own severity rating. It is not possible to kill a character by inflicting only Light Wounds; a character who took 10 Light Wounds would be badly impaired (-10 to all rolls) but would not (immediately) die. On the other hand, there is no equivalent to the "Hurt" Body Level - every wound in ArM5 causes at least a -1 penalty.

Down Time

The rules for "down time" (when characters are not in the lab or going on adventures) are given their own chapter in ArM5, called "Long-Term Events." The changes are relatively minor.

Long-term Fatigue exists in ArM5. This is the same as in Third Edition - it's back. Casting ritual spells can cause long-term Fatigue loss.

The new wound rules in the combat chapter dictate new mechanics for wound recovery, but the basic idea is the same: make a Stamina roll after a certain period of time to see if your wounds improve. ArM5 makes clear what characters can and can't do when they are wounded, and what happens if they try to do something their wounds normally prevent (they have to make a Stamina check to see if their wounds actually get worse). Wound Penalties do not apply to recovery rolls.

The aging rules have been revised. ArM4's "afflictions" are gone; aging "points" accumulate on each Characteristic like "anti"-experience points, decreasing the Characteristic. The total of all aging points determines Decrepitude: PC's with Decrepitude scores of 4 are too frail for most adventuring; those with Decrepitude 5 are on their death beds. ArM5 introduces the aging "crisis," which can potentially kill a character outright.

Rules for experience and advancement have been standardized. Arts and Abilities cost different amounts to improve (at a 1:5 ratio), but the same experience point (if it comes from a generic source of XP's) can be applied to an Art or an Ability. Also, ArM5 explicitly allows adventuring experience points to be spent on Arts.

The book rules have changed a little. For those familiar with ArM4, there are now only two kinds of books instead of three: tractatus and summae (libri quaestionem are gone). New, detailed book rules are given in the Covenants supplement.

ArM5 adds explicit rules for "learning by doing," gaining experience points through exposure.

Studying from vis has been totally nerfed in ArM5, yielding generally fewer XP than what one can gain from books.

There are new rules for "Warping," the negative effects of exposure to strong Auras or supernatural effects. For magi, Warping is the same thing as Twilight Points. Non-magi gain Flaws (and, occasionally, Virtues) as their Warping score increases.


ArM5 includes simplified covenant-creation rules in the main rule book. There is less emphasis on point values for everything: only the library and magic items have to be purchased with a point budget. Covenants in ArM5 have Boons and Hooks, which work for covenants much like Virtues and Flaws work for characters.

There is an ArM5 supplement called Covenants which expands a great deal on the concepts in the core book.

Mythic Europe

ArM5 includes more-specific advice on how to take advantage of the Mythic Europe setting to create unique and interesting stories.

Several issues about the setting are explicitly level up to players to decide for themselves: the level of historical accuracy, the level of organization / enforcement in the Order, how the Church will be portrayed, the level of demonic influence in Mythic Europe, and the ultimate fate of magic.


ArM5 makes clear the difference between the Magical and Faerie Realms. Supplements seem to have resisted the ArM4 tendency to move everything interesting into the Faerie Realm.

The Dominion penalties on magic use are much stronger than in ArM4. Player characters actually have to worry about them.


The ArM5 bestiary is shorter and omits mention of mundane animals. After ArM5 was published, the ArM5 Book of Mundane Beasts was released as a free PDF download.

- Andrew Gronosky and Steve Saunders. Additional thanks: Erik Tyrell

Third to Fourth

Note that this is not a review; this is a changes list, intended to concisely list the major changes between the editions, particularly for those people who are familiar with previous editions and need a quick-reference to rules differences.

The 4th Edition has a somewhat convoluted history. It was originally developed by Wizards of the Coast, primarily by Wade Racine; when Atlas Games purchased Ars Magica from WotC, after WotC discarded its roleplaying lines in December 1995, Atlas Games embarked on a thorough revision of the material. WotC's 4th Edition was very similar to the 3rd Edition of the game. Atlas Games took a different approach, rewriting the text and streamlining the rules; the final result is the product of many authors.

Ars Magica 4th Edition (we'll call it ArM 4, for convenience) is a substantially slimmer book than 3rd Edition (ArM 3). The turgid text that marred ArM 3 has been eliminated, resulting in the same material, and more, being packed into a much smaller volume. Unfortunately, a goodly amount of flavor-text got chopped along with it. Artwork is very sparse, as well. This is a black-and-white book; the layout is simple, the fonts are readable, and the index is accurate.

Organizationally, the books are quite similar, though. As a result, again, the rules come before the background (though the introduction does a decent job of describing the apprenticeship of a magus), and the lack of good character-creation examples is even more pronounced in ArM 4 than it was in ArM 3.

Almost all of the Latin has been fixed to be grammatically correct, at long last. This particularly affects plurals; for example, it the plural for "consors" is now "consortes", not "consortis". It also affects some of the Arts: Corpus, rather than Corporem, and Imaginem, rather than Imagonem.

The setting has been updated from 1197 to 1220, and True Reason has been eliminated. White Wolf seems to have unofficially placed its Vampire: Dark Ages setting in 1197; Atlas Games continues the Wizards of the Coast attempt to separate Ars Magica from any World of Darkness associations.

The changes between the two editions are substantial, and many are fairly subtle. A lot of the changes prevent "rules hacks" that used to be possible. For example, bonuses from Virtues and the Characteristic limits have been reworked so they don't overwhelm Ability scores, and loopholes involving certain spells (particularly Muto Vim) have been closed. "Game balance" is better overall, at least as far as the mechanics go; the obvious power differences between Magi and Grogs, for example, are inherent to Ars Magica and thus remain. The list below is not comprehensive, though I have tried to point out the most important changes.

I do think that ArM 4 is a substantially better ruleset, and ought to be the edition of choice; certainly it should be the edition of choice if one is starting a new Saga.

I am going to follow the ArM 4 order of chapters in my analysis of changes, below.


Ease Factors: The table that explained what was Easy, Difficult, etc. seems to have been eliminated; this has the potential to be particularly problematic for new StoryGuides, who may not know that 6 is supposed to be an Average difficulty task, etc. It is worthwhile to note that most things in ArM 4 are now multiples of 3, in order to fit in with the idea of Ease Factors stepping up by factors of 3. (This is supposed to be corrected in the second printing.)

Maintainer's Note: It was; see the Fourth Edition errata.

Dice: The "quality die" from ArM 2 has returned. This is like a stress die, but the 0 counts as a 10, allowing for extraordinary success but not extraordinary failure. A number of rolls have been chased from stress to quality, such as the roll for damage incurred by falling.

There is apparently no explanation of what a "pace" is. It's about equivalent to a yard (three feet).


The Gift: The social-interaction penalty has been changed back to the way it was in ArM 2, with the -3 only applying to rolls that involve winning the trust and affection of others.

The Houses: Each Hermetic House now comes with base Abilities and possible required Virtues and Flaws; these packages are called House Templates, and the most significant are probably the condensation of the V&Fs for House Bjornaer (resulting in only 1 or 2 Virtue Points being spent for all the necessary Virtues) and House Mercere (the cost of Redcap has been reduced to +1 for both Gifted and non-Gifted Mercere). Certain V&Fs, such as No Sigil, are now House-specific. Also note that Verditius magi are no longer explicitly prevented from getting the bonus for using spell foci; the items they need are now called "casting tools".

Companion Social Class and Grog Status: Companions and Grogs are now required to purchase a Social Class or Grog Status, respectively. They're really the same thing under two different names for Companions and Grogs, and Grog Status also ends up being referenced as Grog Background; I remain puzzled as to why multiple terms were necessary. Nonetheless: these V&Fs incorporate a lot of the concepts and some of the mechanics from the old social-class-related V&Fs, such as Knight and Greater Leadership; some of them also include bonus starting Abilities. Background V&Fs have also been improved and clarified; for example, Further Education grants you an Ability package suitable to a university graduate.

Vocations: These are basically just character-concept aids that carry no over game-mechanical connotations. The Vocation descriptions essentially replace the sample characters given in ArM 3, giving a set of Abilities that might be useful to that vocation, but not actually providing any fully-created sample characters.

Characteristics: The range has changed from +5/-5 to a recommended +3/-3 using the new purchasing method (7 points on a pyramid scheme), or a +4/-4 using the revised random method. Characteristics outside that range cost V&F points (to +4, to +5); a modified Mythic Characteristic that raises a score to +5 and permits one incredible feat a day, plus its new counterpart, Pathetic Characteristic. Specialties in Characteristics no longer have a mechanical influence; they're merely descriptive terms. The text no longer gives example Specialties.

Virtues and Flaws: Companions and Magi both get 10 points to spend on V&Fs in ArM 4; Companions only got 7 points in ArM 3. Grogs continue to get 3 points of V&Fs. There is now an option to allow purchase of more Flaws than Virtues. The Virtues and Flaws are now broken down by cost, rather than category, in a way similar to ArM 2, making it much easier to try to find the description of something. The wording on many of the V&Fs has tightened substantially, eliminating a lot of vagaries in interpretation. There is one very important change: bonuses from V&Fs are NOT CUMULATIVE; the highest bonus is the one that counts.

Hermetic V&Fs: There have been many changes, particularly with costs and bonuses/penalties. I'll only describe the really notable ones. Cyclic magic has been broken into two V&Fs, one for the negative part of the cycle, one for the positive. Method Caster now gives you the cost of the Virtue, not half of it, as a bonus to your Formulaic spell totals. Personal Vis Source is now called Secret Vis Source. Life-Linked Spontaneous Magic now requires the expenditure of Body levels, not Fatigue levels. Continuous Spontaneous Magic, and Aptitude with Elements, have been eliminated. Elementalists now have penalties on non-elemental spells equal to their bonuses, and no initial score in Affinity with Elements. The costs of Magical Deficiencies have changed. There is a Flaw counterpart to Inventive Genius, called Creative Block. Magic Addiction has been rewritten. Non-Spontaneity no longer has a bonus benefit of better Formulaic magic.

Generic Bonuses: Knacks now give you a +1 to a specific Ability for each Virtue point spent, with a limit of +3. Aptitudes have been eliminated. Mastered Ability (Talent/Skill/Knowledge) has been eliminated, and replaced by the +1 Virtue, Cautious with Ability (thus allowing you to buy, say, a +3 Knack with the Ability plus the Cautious with the Ability for the same cost as the old Mastered Ability).

Other V&Fs: Again, there have been many changes, and I'll only list a few important ones. The new versions of the old ArM 3 "Exceptional Talent" Virtues now automatically confer a score of 1 in the appropriate Ability. The V&Fs that affected size no longer adjust Characteristic scores, as they did in ArM 3, eliminating Virtues such as Lithe. Magic Item no longer carries the stipulation that the item must be StoryGuide-designed. A new Virtue, Skinchanger, allows shapechanging into an animal. Noncombatant now prevents magi from learning combat spells (as defined by the StoryGuide). The Werewolf Flaw has been replaced with Lycanthrope. A goodly number of the more extreme V&Fs have been eliminated (Leprosy and Immortal, for example).

Passions: These have been removed from the game entirely, and there's not really anything in the way of equivalents.

Reputations: In ArM 4, the score now reflects the intensity, with a descriptive phrase explaining who knows of the Reputation; in ArM 3, the number reflected in how wide a region the Reputation was known.

Confidence: Confidence works as it did in ArM 2 (without special rules for using Confidence in Personality Trait rolls), with each point expended adding a +1 bonus to a stress roll.

Fatigue: Long and Short-Term Fatigue have been collapsed into just Fatigue.

Encumbrance: The Encumbrance number is now considered negative, so it is added to rolls rather than subtracting from them. This lends itself to a bit of confusion, as Loads are now considered negative as well, but common sense should prevail.


This is really part of the section on Characters in the rulebook, but given the extensive changes to the Ability list, this warrants a section of its own, in this document.

There are some minor changes. Healer's bonus is now one-third the score in the Ability, rather than just being additive, as in ArM 3. Medicine and Chirurgery are now interchangeable (it's puzzling why one wasn't just eliminated, given all the other condensing of Abilities).

The changes to the list are detailed below. It should be noted that Combat, and thus Combat Skills, has changed entiretly, and that new categories of Academic Abilities reflect medieval scholarship.

Acting: Now Craft (Acting).
Alertness: Part of Awareness.
Charisma: Part of Charm.
Church Knowledge: Split into Civil & Canon Law, and Theology.
Church Lore: Now Organization Lore (The Church).
Concentration: Now a Talent, not a Skill.
Debate: Renamed to Disputatio.
Diplomacy: Part of Intrigue.
Dodge: Part of Brawl.
Drinking: Renamed to Carouse.
Evaluate: Part of Bargain (conversion notes suggested Craft).
Fantastic Beast Lore: Part of Legend Lore.
Guile: Now a Talent, not a Skill.
Hermes History: Part of Organization Lore (The Order).
Hermes Lore: Now Organization Lore (The Order).
Humanities: Renamed to Artes Liberales.
Intimidation: Part of Leadership.
Meditation: Part of Concentration.
Pretend: Part of Guile.
Scan: Part of Awareness.
Search: Part of Awareness.
Subterfuge: Part of Guile.
Teach: (Wizard's Grimoire) Split into Disputatio and Lectio.
Track: Renamed to Hunt.

Hermetic Magic

Limits of Magic: These have been condensed into a number of specific Limits, such as the Limit of Divinity; each of these Limits encompasses a number of the old list of limits. This seems to be purely a flavor change.

Spontaneous Magic: This has been clarified slightly, to note that if one does not achieve the attempted Level, there may still be a lesser effect.

Ritual Magic: The elimination of Long-Term Fatigue levels has resulted in a (possibly unintentional) change to Ritual Magic: Fatigue lost here is just like any other Fatigue Loss. Personally, I'd rule that Fatigue lost through casting Ritual Magic can only be recovered through sleep.

Concentration rolls: These have changed slightly. Now, if you fail a Concentration roll, when you roll for the spell to check for a Botch, you incur an extra Botch die penalty. There is no longer a stipulation that Encumbrance modifies the roll if you are moving. Furthermore, the Distraction Table has changed; in particular, the Ease Factor for being damaged while trying to cast has changed to a flat 15, rather than being dependent on the amount of damage sustained.

Mastering Spells: The rules now contain the option for the StoryGuide allow players to assign more than one XP to a spell at a time. There is no longer a restriction on which spells one may spend the XP on.

Multi-Casting: The target number needed to multi-cast is now declared to be, "greater than 9". I am not sure whether this was an intentional change from the old 9+.

Recognizing Spells: The roll is now an Awareness roll, rather than a Perception roll.

Raw vis: The maximum number of pawns you can use in a single spell or round of Certamen is now the highest of the two relevant Art scores (in addition to the old limit of not being able to use more pawns of a single type than your score in that Art).

Certamen: Fatigue loss is now calculated based on every five full points of difference in rolls, rather than five points or fraction thereof.


Scribing Spells: The number of levels of spells that can be scribed, copied, or obscured in a Season is now based on Scribe Latin, rather than just being a flat rate. Laboratory texts are handled in a similar way.

Vis Extraction: This rule from ArM 2 is back, but the rule is now one pawn for every full 10 points of the total, not one-fifth of the total.

Invested Devices: You can now invest items with a set number of charges; such items can also be made rechargeable. Lesser Invested Devices seem to be missing the paragraph that details vis expenditure (one pawn of Art-specific and one pawn of Vim for every 10 points).

Helpers in the Laboratory: The total number of helpers one can have in the lab is now limited to your Leadership Ability score (though you can always have one helper). Lab assistants now explicitly do not gain anything through the cooperation.

Apprentices: The rules for training apprentices have changed completely. There are no longer set rules (1 XP of Magic Theory and a score of 0 in one new Art, per Season; 10 levels of spells per year), as there were in ArM 3; instead, you are encouraged to look at the character templates for guidelines. Quick apprentice generation has thus been effectively eliminated. I am inclined to think that explicit training of apprentices, particularly given the new teaching rules, is also quite likely to produce apprentices who become fairly powerful at a much earlier age.


There are now default ranges, durations, and targets for each of the Technique-Form combinations at varying levels; Spontaneous spells have these parameters unless the player chooses otherwise. The R/D/T of a spell now combines to form its base level. There are also guidelines for spells below level 5, now.

Ranges: These have changed. Personal has absorbed Self and Body. Eye-contact range is considered to be level-equivalent with Touch. A new range, Far (100 paces) has been inserted between Near and Sight. A new range, Arcane Connection, governs spells that have Arcane Connections as their distance limit.

Durations: Momentary has replaced the part of the old Instant duration that governed immediate effects (Pilum of Fire and a lot of other combat spells, for instance). A new duration, Diameter, lasts for two minutes. Ring duration has been clarified, and the caster now has a choice of the size of the ring. Permanent and Instant are now level-equivalent, governing only persistent spell effects or permanent changes.

Target: This is a new spell parameter. It governs exactly what the spell affects: Individual, Group, Room, Circle, Structure, Boundary, Sight.

A few spells (like Change the Nature of Vis) have been eliminated. The descriptions of a lot of spells have changed, and there have been some level changes. The most immediately-noticeable spell change is that the Ball of Abysmal Flame is now a level 35, not a level 30, spell; there are no level 30 Creo Ignem spells given, thus somewhat lessening the power of a beginning "classic Ignem-specialized Flambeau" magus (unless the storyguide permits players to make up their own spells at game start). There are other significant increases in spell levels; for example, Image from the Wizard Torn is now level 30, not level 20. The difficulty of PeIm spells, however, has been substantially reduced (whether or not this will be corrected in the second printing remains to be seen).

Particularly notable is that rolls against Ease Factors for various spell effects are now based off multiples of 3, and that damage is consistently done as multiples of 5. A bit of editorial inconsistency results in spell guidelines and the spells themselves being partitioned off differently by section headers.

Many Vim spells have been substantially altered, and deserve special note here. Meta-magic of the Muto Vim type can no longer be applied to Spontaneous Spells, and the rules on using meta-magic on other people's spells have been clarified; in particularly, you must now beat the Penetration Total of a hostile magus' spell in order to alter it with meta-magic. Shroud Magic now only suppresses or alters the sigil. Wizard's Boost is now Form-specific, and it is explicitly stated that a spell can only be Boosted once. The Aegis of the Hearth spell has been rewritten.


Combat has been revised substantially. Action and Dueling combat no longer exist; there is one unified system. There are some optional rules which really don't do much other than increase or decrease the number of die rolls which need to be made, but just about everything is always rolled (no more flat +6 added to Soak for an Action-combat equivalent, for instance).

Combat skills are now completely different; you buy fighting styles rather than buying specific weapon and shield skills. For example, if you fight with a Shield and Weapon Skill, you can use a Mace and Kite Shield, Longsword and Kite Shield, Shortsword and Buckler, etc.; more exotically, Two Weapons skill covers everything from the standard two shortswords to cloak-and-dagger and net-and-trident. Of course, each weapon combination carries its own base totals, ranges, and so forth.

Combat totals are calculated in a fairly similar way, with a combatinion of a Characteristic, Skill, Encumbrance, and Weapon Bonus. The old First Strike total has been subsumed into a more general total called Initiative.

The combat phases remain similar to their previous incarnation. Combat ranges are now considerably more important than they used to be; weapons all have optimum ranges, with penalties applied for attempting to use them outside that range. There are rules of engagement which govern closing with opponents, and so forth.

One very important difference is that the difference between opponents' Attack and Damage rolls is now applied towards the Damage done, or towards an advantage bonus in the next round. Thus, one can "save up" for one really devastating blow, allowing, for example, a character who is very skilled with a dagger to dance around someone heavily armored and still be able to penetrate that armor with that one final blow that goes through a chink. The combat system is thus rather reminiscent of the Certámen rules.

It should also be noted that Size now adds to Damage and Soak directly (and still subtracts from Defense Totals, as it did in previous editions).

You now lose one Body Level per five full points of Damage-Soak differential, rather than per five points or fraction thereof.

Combat Fatigue rolls (against 6+, but weapon skill is added to the roll) at the end of each round are now required for everyone engaged in melee combat, rather than only being required when switching actions.

There are new rules for dealing with multiple opponents, as well as modified Brawling rules to deal with the increased importance of range. The special attacks like Great Blow and Desperate Defense have simply become All-Out Attack or Defense. The Combat Botch chart has been eliminated; unfortunately, no examples have been provided in its place. There's also a basic rule for armor improvement, more or less trading protection for load on a one-for-one basis.


This section probably represents the meatiest changes in rules, introducing completely new rules for most of the core long-term character development mechanics.

Aging: The aging rules have been completely changed (they're more or less like the rules that I posted to the Ars Magica mailing list). Penalties are now based on "afflictions", rather than Characteristics loss; for example, a character might go blind over the years, resulting in penalties to rolls involving sight, equal to the affliction score.

Experience: Experience gained outside of adventures now is gained either through an entirely new set of rules; there is no longer a flat rate of X number of points per Season. There is Training, Practice, Exposure, Lectio and Disputatio (formal teaching of Knowledge or Lore from a text or through the Socratic method, respectively), and learning from books. Magi can also train each other in spells, and can practice in order to Master spells. Finally, magi also gain 1 XP in Magic Theory for each Season spent inventing a spell, enchanting an item, or making a potion, unless working from his own lab text.

Books: Book rules have been drastically changed. Books now fall into the categories of summae, libri quaestionum, and tractatus; most books have both a Level and a Quality. Rules for scribing books and learning from them are much more detailed than in ArM 3.

Arts: Arts now have both a score and XP in them, in a fashion much like Abilities; XP for Arts is completely separate from XP for Abilities. Purchasing new scores in Arts throughout the Saga is thus like purchasing them at the outset; for example, you need to gain 25 XP in the Art to go from 24 to 25 in that Art. The change in rules is fairly smooth; for example, learning an Art from vis is done the same way, except you add the raw total as XP to that Art, rather than seeing if you go up 0, 1, 2, or 3 ranks in that Art (but there's still a limit of 3; extra XP is lost). This means that it is now much easier to gain high Art scores, since Seasons are never completely wasted unless you Botch.


The covenant creation rules have been rewritten again. They share a lot of base similarities to the rules from the ArM 2 supplement Covenants. This is a purchase-point system, based on eight characteristics, each with three sub-characteristics called Traits. Together, they provide a fairly detailed picture of the covenant; there is no real equivalency between the various previous version of covenant-generation rules.

-- Lydia Leong

Second to Third

I do want to bring up the most important difference between the two editions: the 2nd edition is concise and the writing is fairly reasonable. The 3rd edition is verbose and the editing is amazingly poor. The 3rd edition smacks of, "paid by the word", and the sheer amount of excess text is mind-boggling. I strongly encourage the people working on the 4th edition to not repeat 3rd edition verbatim, but to actually rewrite the paragraphs involved. Even if no _real_ material is actually cut, simply trimming down the writing style would eliminate countless pages of text.

I also want to note that I think the Introduction to the 2nd edition is a lot better than the 3rd, and that first page of ArM 2 is a lot more effective in conveying the essence of the world than the first bits of gray text in ArM 3.

Nonetheless, here we go with the diffs between the editions; this might not be a complete list, but I hope it's relatively thorough. The order follows the order of presentation in the 2nd edition book. Do note that there's a lot of stuff added to the 3rd edition which isn't in the 2nd edition at all. I may get flamed for this statement, but given the sheer number of changes to even the basic rules, I think that claims of the One True Edition are a bit hard to make (at least given the fact that most of the people on the mailing lists apparently use the 3rd edition rulings, and add some things out of 2nd, like vis extraction).

Below, when referring to location in the rulebook, something like, "xC yP" refers to x column, y paragraph (i.e., "2C 3P" is the 2nd column 3rd paragraph). Items in quotation marks are actual quotes; everything else is my own commentary. I have only put citations in places where the rule might be difficult to locate.

I've noted places where I, personally, think the ArM 2 rule is better, and also thrown in a few general suggestions for 4th edition.

Character Creation

ArM 2, p. 14, 1C 2P: if you have a powerful mystical ability, you also suffer the -3 to social stuff that the magi do. (Presumably this refers to Exceptional Talents. 3rd edition has the -1 Flaw Magical Air instead.)

Beginning age: This is randomized in ArM 2, and chosen in ArM 3. It would be useful for good starting ages to be noted; particularly, ages should be noted for beginning magi (since your apprenticeship begins between age 7 and 17, and lasts 15 years).

Characteristics: Pairs have to be balanced in ArM 2 (the two characteristics in a pair have to be within 1 of each other), but not in ArM 3. (ArM 1 required the pair balance within 3 of each other.)

The Gift: ArM 2 imposes the -3 penalty on social interaction which involves people trusting you; ArM 3 imposes this on all rolls involving interacting with normal people (Presence and Communication).

Virtues and Flaws: Companions and Magi both get 7 points in ArM 2 (magi get 10 in ArM 3). Grogs only get 1 point in ArM 2 (as opposed to 3 in ArM 3). The V&Fs themselves have changed pretty substantially. I don't like the organization in either edition; it'd be nice to have a table summarizing V&Fs by cost, and then break them down in the same way ArM 3 does -- but PLEASE LIST THEM ALPHABETICALLY within each section (I've found it immensely frustrating to know a flaw name, cost, and section it appears in, only to not be able to rapidly locate it within that section).

Character Templates: the short little blurb templates in ArM 2 (p. 34, 35) are a lot better than the full templates in ArM 3. The "instant grog" (ArM 2, p. 22) is also a nice touch. They don't take up much space; I wish they'd appear in ArM 4. (What's badly needed, IMHO, is a list of typical V&Fs for each House of the Order, since this information was, by and large, left out in Houses of Hermes.)


Eeveryone in ArM 3 begins with 3 Confidence Points; in ArM 2, it's 3, 2, and 1 for Magi, Companions, and Grogs, respectively. The Confidence rules are completely different. To quickly summarize:

In ArM 2, you can declare use of X points of Cnf BEFORE making a stress roll, and add the number of points to the roll. If you make the roll, you keep the points. If you roll the Ease Factor exactly, you make a simple roll; if the roll if higher than your maximum Cnf (i.e., what you had before spending any temporarily), then you permanently gain 1 Cnf. If you fail, you lose the spent points for the duration of the story (or until the SG says otherwise, basically). If you botch, you lose 1 Cnf permanently; you always have at least 1 Cnf, though. There are also special rules for using Cnf on Personality Rolls.

In ArM 3, you can declare that you are spending a Confidence Point, after a failed stress roll. You then get a reroll. If you make the roll, you keep the point. If you fail it, you lose it for the duration of the story. If you botch it, you lose the point permanently. You cannot use Confidence more than once per action. Confidence can also be spent on Passions (different rules). Gaining Confidence can only be done via StoryGuide fiat. There is no stated minimum for Confidence points.

Reputations: these rules have increased in complexity in ArM 3; notable is the stress roll that is sometimes involved in losing Reputation.


In ArM 2, Grogs get their age + 10 in initial XP to spend; in ArM 3, Grogs get their age * 2 (same as Companions).

In ArM 2, Abilities can be reduced below 0 (to a minimum of -3), for the gain of 1 point per point reduced. However, to buy a negative ability up is "normal"; i.e., to go from -3 to -2 costs 3 points.

ArM 2 also says things like, "Drop all fractions." It'd be nice to have a consistent rounding scheme, which apparently doesn't exist in ArM 3.

The abilities themselves have been modified in various ways.

Penalties for using abilities you don't have:

Talents: ArM 2, roll normally. ArM 3, roll but with 3 extra Botch Dice.

Skills: ArM 2, penalty of -2 to -8, and/or 1-3 extra Botch Dice (decision of the StoryGuide, presumably). ArM 3, penalty of -3 and 3 extra Botch Dice.

Formal/Arcane Knowledges: can't do it, both editions.

Casual Knowledges: ArM 2, penalty of -3 to -10. ArM 3, roll normally.

The "roll manipulation" stuff is only in ArM 2 (it's extraneous).

Experience in ArM 2 is a constant: in a story, it's 3 for magi, 2 for companions, 1 for grogs, plus any bonuses. ArM 3 makes it StoryGuide fiat (a far more reasonable way, since the ArM 2 way really kinda denigrates the contributions of the non-magi).

There is no Yearly Experience in ArM 2, though there is in both ArM 1 and ArM 3.

Aging and Decrepitude

There is a major difference in the two editions, here.

ArM 2 begins aging at 35 + Stamina; ArM 3 begins it at 35, period. (I think the ArM 2 version is more reasonable, personally, since high Stamina should help with aging, which it doesn't, in ArM 3).

In ArM 2, to do an aging check, you first state the Characteristic you've used most often this year, and then make a simple roll, consulting a Characteristic Loss chart. If the characteristic chosen by the chart is the one you stated you used most often, the roll gets a +3. The roll gets -1 for every point of Decrepitude you possess. A longevity potion adds a flat +5 to the roll. On a roll of 5 or below, the Characteristic doesn't drop; otherwise, it's lowered by 1 point.

In ArM 3, aging has several steps. First, there's a roll to see if any characteristic drops at all. This roll is modified by +1 for every point of Decrepitude, and decreased by a longevity potion (the effectiveness of which is based on the InCo lab total of the magus who created it, at the time of the creation). If this roll indicates Characteristic loss, a simple roll + that Characteristic is made; if the roll is below 7, that characteristic is decreased by 1.

Decrepitude in ArM 2 also modifies healing rolls and the number of Botch Dice rolled on Soak botches. Decrepitude isn't used in either of those ways in ArM 3 (or at least, if it is, I can't find the rules for it).


I've looked this bit over a little less carefully than the rest, and thus didn't spot any big changes (other than the obvious split of combat into Action and Dueling systems).

Falling damage for falling on a hard surface is, in ArM 3, explicitly doubled after Soak is applied.

ArM 2 states that poisons can simply be handled as damage against which the Soak roll is based solely on Stamina + Size.

Plate Armor has been removed from the Armor Protection Chart in ArM 3. All Plate, in ArM 2, is Expensive; stats are as follows: Plate Cuirass (prot. 10, load 4), Plate Hauberk (prot. 15, load 6), Full Plate Armor (prot. 17, load 7).

One note, though: the Combat Botch suggestions in ArM 2 seem a lot more reasonable and useful for coming up with one's own Botch ideas.


Magic Resistance: the roll for Parma Magica in ArM 2 is simple; it's stress in ArM 3. (In ArM 1, Parma Magica is an actual spell, not an ability.) ArM 3 allows you to also suppress your Form bonus by concentrating. ArM 2 does not allow this, but it does allow you to subtract your Vim score from your Magic Resistance, by concentrating.

Fast-Casting: ArM 2, -5 penalty on roll, plus double Botch Dice, and a roll of 0 indicates a side effect (whether or not you Botch). ArM 3, -5 penalty on roll, with 3 extra Botch Dice. (The chart for ArM 3 mentions a side-effect, but the rules do not; WotC has confirmed that the chart is erroneous.)

Spontaneous Spells: ArM 3, you must always roll a stress die if you are Fatiguing yourself (p. 173, 2C 3P). ArM 3 also gives a "similar spell" bonus of +1 for every 5 levels of a similar known Formulaic spell. ArM 2, however, allows up to a +5 bonus for a colorful description of the spell (a roleplaying modifier, essentially).

Strengthening Formulaic Spells: in ArM 2, with non-ritual Formulaics, you can double the effect by expending 1 pawn of vis for each 5 levels of the spell (I think -- this is really poorly worded, ArM 2 p. 69: "For non-ritual formulaic magic, each point of raw vis duplicates 5 Levels of the spell. Thus you can double the effect of your spell by using 1 raw vis point per 5 levels of the spell.") In ArM 3, this weirdness doesn't exist; spending a pawn of vis simply adds +5 to your spellcasting roll.

Words and Gestures: ArM 3 states explicitly that casting without gestures negates Encumbrance penalties.

Using raw vis: in ArM 2, the maximum vis you can expend at a single time is your Vim score. In ArM 3, the maximum amount vis of a single Art you can expend at a single time is your score in that Art. In other words, if you have Creo 5, Ignem 3, Vim 4, and are casting a Creo Ignem spell, in ArM 2 you would be restricted to expending 4 pawns total (but it can be of any type), whereas in ArM 3, you could expend up to 8 pawns (5 of Creo and 3 of Ignem) but it must be either Creo or Ignem vis.

Vis in general: the concept of Art-specific vis is basically non-existent in ArM 2. Furthermore, in ArM 2, if you expend vis, you must expend all the vis you are touching; in ArM 3, you can decide how much you use.

Casting from a text: in ArM 2, the spell goes off whether or not you go Unconscious; in ArM 3, the spell fails if you go Unconscious.


Many spell descriptions have changed, of course.

One to note is the Aegis of the Hearth. In ArM 2, for spells entering the Aegis that have a target which would normally get a Resistance Roll, the target gets Level of the Aegis + 5 added to his Resistance Roll, thus making it much more likely that such spells will fizzle (spells that don't fit this get Level of the Aegis + 5 + die -- presumably a simple die). In ArM 3, it's just a flat resistance to all spells: Aegis + 5 + stress die.

Realms: The power interaction chart has been vastly simplified in ArM 3 (ArM 2 had the weird change in multipliers depending on Aura strength).


In ArM 2, the loser of a round drops a Fatigue level for every 5 points of exceeded resistance roll. In ArM 3, the loser drops a Fatigue level for every 5 points or fraction thereof.

ArM 3 allows explicit surrender before going Unconscious; the finishing spell can still be cast, but the loser's Parma Magica is not circumvented.

In ArM 2, the finishing spell must be of EITHER the same Technique or Form (or both); in ArM 3, the finishing spell must be of the same Technique AND Form.

In ArM 2, vis may be expended in the Certamen at any time. In ArM 3, vis can only be expended in the opposed roll (the one that involves the Form and Technique scores), not in the roll-to-weaken and its resistance roll.


The rules for studying/copying knowledges are only in ArM 2: you gain 3 XP in a knowledge per season of study, and your score cannot exceed the source's (usually a book). You can record 1 point per Season but cannot write more than half your score; you can copy at 3 points per season.

When studying from vis, in ArM 3, you add the rating of your Aura, to roll * pawns, in order to get the total effective score. In ArM 2, it's just roll * pawns.

The rules for vis extraction are only in ArM 2: you can extract, in a Season, a number of pawns of Vim vis equal to one-fifth of Creo + Vim + Magic Theory + (3 * Magical Aura).

Instilling effects: in ArM 2, you must equal the level of the desired effect with your lab total, in order to instill it. In ArM 3, you gain 1 point towards instilling the effect for every point your lab total is ABOVE the level of the effect; the effect is instilled when the accumulated points equal the effect level. In other words, it's MUCH harder to instill effects in ArM 3 (but there are no Lesser Enchanted Devices in ArM 2).

Potions: in ArM 2, the base total is your lab total plus three times the Aura; in ArM 3, it's your lab total plus the Aura. In ArM 2, expending vis increases this total by +3 per pawn; in ArM 3, expending vis for the appropriate Art(s) increases this total by +5 per pawn.

Longevity potions: the ArM 3 rules are more complicated, due to the change in aging; see above (and p. 107 in ArM 2 and p. 250 in ArM 3).

Magic Foci vs. Talismans: ArM 2 uses the former; ArM 3 uses the latter. The two serve the same function, under different names (a "spell focus" in ArM 3 is no longer an enchanted item, but a simple object used to give a bonus to a specific Formulaic spell). Both editions require that a Season be spent preparing the item for enchantment. ArM 3 also requires that an additional Season be spent attuning it as a talisman; a talisman in ArM 3 is also an Arcane Connection to you.

Distractions from Studies: ArM 3 reduces the penalties for being away; the first 10 days are "free", and after that it's 1 level of book study lost for every 2 days away, or -1 to the lab total for every 1 day away. (ArM 2 does not give any "free" days, and it's a -1 penalty to the lab total for each day; there's nothing said about study.)

Lab Texts: These only exist in ArM 3.

Familiars: Familiars have "familiar powers" in ArM 2; in ArM 3, there are "bond qualities" instead. The two are substantially different. ArM 2 there is one power for every Art, and a score of 15+ in that Art is required to enchant that power. ArM 3 allows the simple purchase of positive and negative aspects of the bond, which affect the way master and animal interact, rather than being overt powers of the animal itself.

Vis: for most magical activity, ArM 2 does not state that Art-specific vis must be used.

A lot of good Saga/playstyle material was cut or rewritten between ArM 2 and 3; I'm of the opinion that the simple directness of the ArM 2 stuff is more effective than the verbose moodiness of ArM 3.

-- Lydia Leong

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