Inventing Spells

See the core rulebook for full details, but a summary and some reference materials are available here.

Spell Level:

Each spell starts with a base level based on its effect, chosen from the tables for the appropriate combination of arts given in Chapter 9. Afterwards, spells are increased by one magnitude at a time by increasing their Range/Duration/Target effects. Note that a magnitude normally equals 5 levels, but for effects of below level 5 they only add or remove a single level. Thus, starting with a 1st level effect and repeatedly adding magnitudes to it, the spells level will proceed as follows:

1-2-3-4-5-10-15-20-25-30-35-40-45-50… etc

All spells start at Range: Personal, Duration: Momentary, Target: Individual. These can be increased as follows (note that options separated by a slash are separate choices):

Range

Personal (free) only affect self
Touch / Eye ( +1 mag) affects target touched / eye contact recipient
Voice (+2 mag) reaches where your voice reaches
Sight (+3 mag) reaches where you can see
Arcane Connection (+4 mag) any target you hold a connection to, such as hair or clothing

Duration

Momentary (free) happens
Concentration / Diameter (+1 mag) as long as you focus / 2 minutes
Sun / Ring (+2 mag) until next sunrise or set / until a physical ring is broken
Moon (+3 mag) until after next new and full moon
Year (+4 mag) until 4th equinox or solstice after casting

Target

Individual / Ring (free) single discrete person or thing / everything inside a circle
Part (+1 mag) portion of a thing
Group / Room (+2 mag) collection of people or things / everything in a room
Structure (+3 mag) everything in a structure
Boundary (+4 mag) everything in a natural or man-made boundary, like a valley or walled city

Inventing Spells

Ars Magica: Hibernia DM_Josh DM_Josh