_Summae et Tractatus_

The following rules for Summae and Tractatus (yes, Tractatus is singular and plural) include some of the modifications in ArM5’s Covenants and house rules.


A Summa is, as you might expect, a text that summarizes a wide field of knowledge. A text that summarizes a narrow field or is written concisely may be called “summula”—literally a little summa—but the rules for their construction and use are identical to those of a summa.

Every Summa has two important numeric values for game mechanics: Level Range (L) and Quality (Q).

Level Range (L): Yes, this modifies the core rule. Not every Summa written is accessible to neophytes on the given subject, and almost no Summa contains all the advanced knowledge that exists on the given subject.

With these limitations in mind, every Summa has a Level Range. The lower number is the level you need in the given Skill to benefit from reading the text. (If the lower number is 0, then naturally you don’t need any prior experience with the Skill to benefit from the summa in question.) The higher number is the maximum Skill level to which you can raise the given Skill using that summa; once you reach the maximum Skill level, any additional XP you’d normally gain in a season of studying the summa is lost.

For example, Natan Utbrott, otherwise a Flambeau extraordinaire, actually has no skill in the Art of Ignem, and he’s decided it’s time to fix that. He grabs Da mihi fomitem, da mihi ignem, a summa on Ignem (by Laurentius Huldericus et al) with a Level Range of 0-8. He can learn the Art of Ignem from this tome. However, if the Level Range had started at 1+, it would be all but useless to him to study it.

Quality: Per core rules.

Summa as reference: Furthermore, Summa aren’t just instructive texts. They’re reference material. Every Summa has a Skill plus a title and/or a description. If the listed Skill and either the title or description or both suggest that the summa would have some useful information when researching the answer to a question, the summa can be used to gain a bonus on the subsequent Skill Check. This bonus is at least +1 but rarely more than that. The researcher must have the minimum level noted in the Level Range to gain this bonus.

Let’s check in with Natan Utbrott in the following season. Somehow, his covenant—Horologium mortis—woke up a troll in yonder lake. Somehow, he’s the only magus there with Faerie Lore. Therefore, he’s the lucky guy who gets to figure out how to deal with the unseelie terror. Consulting the covenant library, he locates Wee Folk and Not-so-wee Problems, a Summa on Faerie Lore (L0-4 / Q6). There’ll be something useful in there—however small—for his predicament, so after he takes some time to flip through the pages, he will gain a +1 bonus to the total of his Faerie Lore check. (Too bad his player rolled a 2. With a total check of 6, Natan Utbrott will have to look elsewhere for answers. Maybe the tavern. Yeah, ale always has the answer. . . .)

_Summae et Tractatus_

Ars Magica: Romandy Tyvent