NB: For this Ars Magica node, I am working from my experience primarily with 3rd edition texts and gaming, but from a few 4th edition texts as well
"Salve. Magus Ellylldan has asked me, as librarian here at Covenant Sedes Silva, to assist ye in learning more about us.
"Magical theory? Seems an odd thing fer one without the Gift to be worryin' about. Ach, well, I suppose t'will do ye no harm. Without the Gift, ye ken, it will be nothing more than Latin to ye, after all. Ye willna be able to perform any miracles yerself.
"It's the parma magica ye'd be interested in learning about, then? Well, let's take a look here under House Bonisagus; he was the first one to come up with the parma, and the greatest theoretician the Order has yet known, and one of its founders, too.... Here, be ye able to read this, or shuld I translate it for ye?"
"Literally, 'magic shield,' the Parma Magica was invented in the early 8th century by the Magus Bonisagus, founder of the Hermetic House of the same name. At the encouragement of the Maga Trianoma, he founded the Order of Hermes, the first formal union of wizards allowing them to share information and work together with some assurance of safety; and codified a rough general theory of magic."
A parma magica is a Hermetic Skill in the role-playing game Ars Magica. It is one of the most heavily debated aspects of the game, and many gaming groups have created specific house rules to deal with their respective concerns and/or criticisms. A Magus's Parma Magica Ability contributes significantly to his or her Magic Resistance defense against those spells and powers that can be resisted.
Magic Resistance covers only you and anything you wear or hold in your hands (not anything you are merely touching or that extends far from your body). Magic Resistance is automatic, as long as your Parma Magica is active. You may elect not to resist a given spell, dropping your Parma Magica temporarily by willing it so. If you do drop it in this way, it returns when you concentrate on it, and continues as normal until the next sunrise or sunset. Note: Any spell with range Self or Body that you cast on yourself automatically circumvents your Magic Resistance, so you do not need to drop your parma for these.
Parma Magica is not a spell, but a type of ritual (but it is not "Ritual Magic," which has a specific definition).
Parma Magica: Performing a magic ceremony to protect you from magic. The ceremony takes about a minute to perform. Once performed, the ceremony lets you add 5 times your [parma magica] Ability score to Magic Resistance rolls until sunrise or sunset, whichever comes first. You may also protect one other person for each point in your Ability score, but your score is effectively 3 points lower [for everyone, including yourself] when protecting others (so you need a score of 4+ to do any good at all). You may cancel the effects of the ceremony at will. Specialties: protection from any Form or Technique
Only a magus may possess the Parma Magica skill. Companions and grogs may not.
When protecting others with your parma, you must intentionally do so at the time that you perform the ritual; newcomers cannot be added until the next time the ritual is performed (of course, the magus may decide to perform it immediately). They must remain within 15 paces of you to maintain that protection. If a protected individual leaves the area, he or she personally loses the protection, but everyone else retains the same Magic Resistance (it is not adjusted up or down); if the individual returns within 15 paces, his or her Resistance is regained.
Under book rules, a parma remains fully in effect no matter how many spells it has resisted, and its protection is all or nothing: spells are either resisted or they are not. The term "ablative parma" has been invented for those house rules wherein either the Parma Magica "weakens" any incoming spells that it doesn't totally stop; or the parma itself is weakened through repeated contact with magics that it stops or weakens; or both.
Certamen and Parma Magica
Certamen is a formalized type of magical combat among wizards. Should you cause your opponent to lose consciousness during a certamen, you are entitled, if you choose, to cast a single spell at your opponent, whose Parma Magica is automatically circumvented.
Virtues and Flaws Affecting Parma Magica
Rather than reproducing the text of the individual virtues and flaws, which may be found in the rulebook, I will provide only their names.
- -1 Flaw: Flawed Parma
- -3 Flaw: Isolated from the Order
- -3 Flaw: Weak Parma
- -4 Flaw: Susceptibility to Faerie Power
- -4 Flaw: Susceptibility to Infernal Power
- +4 Virtue: Magic Resistance
Familiar Bond Quality Affecting Parma Magica
Rather than reproducing the text of this bond quality, which may be found in the rulebook, I will provide only its name.
- +5 Bond Quality: Shared Protection
Under normal circumstances, a Familiar uses your Forms or its own Magic Resistance, whichever is better, to resist spells. It can use a Parma Magica, if you include it in one, but not in conjunction with its own Magic Resistance. You and your familiar can each circumvent the other's Magic Resistance at will.