Project: Redcap; the crossroads of the Order



From Project: Redcap

Each summa is described by two factors: its level, which represents how much knowledge is contained in it, and its quality, representing how well it is written.


A summa (plural, summae) in ArM5 is simply a book that can be studied for multiple seasons. They are an important part of most covenants' libraries. Summa may be used to learn any Art or Ability.

Although he acknowledges that he is not a professional medievalist, Michaël de Verteuil, commenting on and suggesting rules changes for Fourth Edition in the Hermes' Portal fanzine article Ex Libris (part of the latest Heretic's Corner installment in issue 4), noted that the Ars Magica rules give the impression that summa were the starting point for midieval learning, when in fact tracti were the basic texts used in formal education. If you're up for it, see the Wikipedia article on summae.

All the same, reference to summa still gives a good, if inaccurate, feel to the period.


The first printing of ArM5 contained some confusing text about summae that has been clarified by the official errata. On page 165, the text in question reads, "Summae: Source - Quality and Level".

Not as clear as it might be, true. The called-out sentences in the left-hand column just give the stats for the books. The words after the colon should not be capped. The rules are the same as for everything else: Advancement Total is based only on Source Quality, not level.
--David Chart, Atlas Games Discussion Forums, 11 Feb. 2005

All the text is really supposed to mean is that summae have two statistics: Quality and Level. Contrast with Tractatus, which have only a Quality score (no Level).

Summae in Past Editions[edit]

In ArM4, summae were described as books "distilling all that a scholar knows about an Art or Knowledge into a single book." (page 188). The formula for determining the Quality of the summa was somewhat different than in ArM5, but the general rules for studying from them were similar.

In ArM3 and earlier editions, there was only one sort of book. Summae as such did not exist (although all books were similar to summae in that they could be studied for more than one season).


  • Studying from summae, ArM5 p. 165
  • Writing summae, ArM5 p. 165
  • Value of summae in a covenant library, ArM5 p. 71

See Also[edit]

Legacy Page[edit]

The history of this page before August 6, 2010 is archived at Legacy:summa