Project: Redcap; the crossroads of the Order


Magic Theory (Ability)

From Project: Redcap

The Arcane Ability, Magic Theory[1], represents an Ars Magica character's proficiency in understanding and correctly applying magic theory. Magi use it extensively used in their laboratory activities, such as inventing spells and creating enchanted devices.

Learning Magic Theory[edit]

All magi need a certain minimum score[2] in Magic Theory to comply with ArM5 rules. It's advisable to create a magus character with a higher score than that bare minimum.[3]

Non-magi can learn the Magic Theory Ability (note that access to all [[Arcane Ability|Arcane Abilities at character creation is restricted), but it primarily useful only to characters who work in an Hermetic laboratory: magi, apprentices, and familiars. One of the few uses non-magi have for Magic Theory is in copying books: scribes who copy books on the Arts need a certain score in Magic Theory or else they will produce corrupted copies.[4]

Uses of the Magic Theory Ability[edit]

The Magic Theory Ability is very important to a magus because it affects practically all of a magus's laboratory activities. Specifically:

  • It is used to calculate the magus's Lab Total.[5] It also determines the bonus to Lab Total a magus can get using experimentation.[6]
  • At character generation, a magus's Magic Theory score partly determines the maximum Level of the formulaic spells he can know.[7]
  • It determines the amount of raw vis a magus may use in a season of lab work.[8]
  • It determines how many different pieces a magus can combine into a single enchanted item to obtain different shape and material bonuses.[9]
  • A magus needs a certain minimum score in Magic Theory to set up his own laboratory[10]
  • When creating an advanced magus character (one who has been out of apprenticeship for several years before starting play), the character's Magic Theory score determines how many enchanted items he may have[11]
  • A score in Magic Theory is required to serve a magus as a laboratory assistant.[12] The Gift is normally required as well[12], but failed apprentices[13] are an exception.
  • Magic Theory is used in certain Mysteries, such as Potent Magic[14] and Bind Curse.[15]

Alternatives to the Magic Theory Ability[edit]

Magi of House Merinita can use their score in Faerie Magic in lieu of Magic Theory under certain circumstances.[16]

The Mystery of Vulgar Alchemy uses Magic Lore in addition to Magic Theory.[17]


  1. Ars Magica Fifth Edition, p. 66, "Magic Theory
  2. Ars Magica Fifth Edition, p. 32, "Magus Only -- Apprenticeship"
  3. Ars Magica Fifth Edition, p. 32, "Hermetic Magi Recommended Minimum Abilities"
  4. Ars Magica Fifth Edition, p. 166, "Corrupted Copies"
  5. Ars Magica Fifth Edition, p. 94, "Basic Laboratory Activities"
  6. Ars Magica Fifth Edition, p. 108, "Inventing a Spell by Experimentation"
  7. Ars Magica Fifth Edition, p. 29, "Detailed Character Creation Summary" (inset)
  8. Ars Magica Fifth Edition, p. 94, "Vis"
  9. Ars Magica Fifth Edition, p. 97, "Preparation for Enchantment"
  10. Ars Magica Fifth Edition, p. 94, "Creating a Laboratory"
  11. Ars Magica Fifth Edition, p. 32, "Magus Only -- After Apprenticeship"
  12. 12.0 12.1 Ars Magica Fifth Edition, p. 103, "Help in the Laboratory"
  13. Ars Magica Fifth Edition, p. 42, "Failed Apprentice"
  14. Houses of Hermes: Mystery Cults, p. 6, "Potent Magic and Potent Spells"
  15. Houses of Hermes: Mystery Cults, p. 131 "Bind Curse (Major House Mystery)"
  16. Houses of Hermes: Mystery Cults, p. 88, "New Abilities"
  17. The Mysteries Revised Edition, p. 32, "Vulgar Alchemy -- Minor Hermetic Mystery Virtue"