How big is a summa? How much parchment is required for a given text? These sorts of questions have not been addressed by published Ars Magica rules, but are interesting enough that a saga rule is appropriate to provide some guidance for the Bohemian Rhapsody Saga.

A few notes about medieval manuscripts. As noted in Covenants (86), most texts are either volumina (rolls) or codices. Unusual alternatives are always possible, but this saga rule will concentrate on volumina and codices. A volumen is created by sewing sections of parchment together lengthwise, and rolling the long strip onto one or two handles, while a codex is created by combining folded parchment folia together into gatherings, and sewing them onto a spine, bound between two covers.

Both volumina and codices are composed of folia: a folium is a single 'leaf' of parchment; for the purpose of this saga rule, the sections of parchment in a volumen are considered folia. Nearly all volumina consist of folia solita ('usual') width, about ten inches across. Narrower or wider rolls are possible, but uncommon. The convenience of the volumen format is that parchment can be joined to meet exactly the length needed; and if more text is needed later, more can be joined. Many volumen do not exceed 20' in length, but lengths up to about 30' are manageable.

Codices are more complex, because their size is a function of the size of the folia used (height and width), and the number of folia gatherings used (thickness). The most common gathering is a quaternio, which consists of four bifolia sewn togethor onto a single binding cord. Each quaternio thus has eight folia, or sixteen page-sides. Other arrangements are possible for gatherings: a single folded sheet is a bifolium; two folded sheets is a duernio, and three folded sheets is a ternio. Greater gatherings are also possible: five folded sheets is a quinternio, and six folded sheets is a sexternio. However, because greater numbers of sheets in a gathering are harder to work with, both for the scribe and for the binder, the quaternio is the most common arrangement. Lesser gatherings are used where a full quaternio is not needed.

Because the folium is the basic unit of text size, this saga rule will determine text size by determining the number of folia required for a given purpose. Three main types of text will be considered: summae, tractatus, and textus laboris.

For textus laboris, assume one-half folia per effect level. A level 10 effect would require five folia, a level 25 effect would require at least thirteen folia, and so on. While a higher-level spell or enchantment might require an entire codex, many textus laboris will be volumina, as it is a convenient format to use for that purpose. Multiple volumina could be used for an effect, or multiple low-level effects could be combined into one volumen. Assuming a width of ten inches, each level of effect requires about one foot of volumen. Because volumina longer than thirty feet are unmanageable, effects greater than level 25 are typically written on two or more volumina, or are bound in a codex. Because most textus laboris do not contain much illumination, these calculations assume a general lack of illumination. If a textus laboris contains illumination, additional length should be acounted for (ten to twenty percent more).

Textus Laboris Volumen: one foot per effect level

Textus Laboris Codex: one-half folium per effect level

Tractatus are assumed by the rules to contain roughly equivalent amounts of content. This saga rule assumes that twelve folia are required for a tractatus. Adding high-quality illumination (illuminatus) adds 20% to that number, bringing the requirement up to fifteen folia, or roughly two quaterniones. However, many tractatus are volumina; a single tractatus with minimal illumination requires a twenty-five foot volumen, illuminatus increases that to thirty feet, the typical maximum length for a volumen. Thus, many or most tractatus will be volumina, as that format is convenient for that kind of text.

Tractatus that are commentaries (commentariola) incorporating quotations from the commented work (annotata), also require more parchment, up to twice as much parchment. Thus, a commentariolum annotatum would either require two volumina, or would be bound as a codex.

Tractatus Volumen: 25 feet in length

Tractatus Volumen Illuminatus: 30 feet in length

Tractatus Codex Illuminatus: fifteen folia

For the purpose of text capacity, the quality of a text is not directly relevant, as the quality is assumed to be only loosely related to the number of words written. While it is true that a sparsely written text might be of lesser quality, or that verbiage might result in a longer text, those aspects are not mandated by the quality of a text. A Troupe or Storyguide may decide that greater or lesser length is appropriate for a given text to reflect reduced quality, independently of this saga rule.

Summae are nearly always codices. While it is possible that a very basic summa might fit onto a volumen, or that multiple volumina could be used for a higher-level summa, most magi in the 13th century expect that a summa will be a codex, or possibly multiple codices for a high-level summa. Summa by their nature are lengthier than other texts, and thus many more folia are typically required for a summa.

To determine the number of folia required for a given summa, use the Advancement Table (ArM5, 31), treating the level of the summa as the Score. If the subject of a summa is an Art, use the Art column, or if the summa is about an Ability, use the Ability column. In either case, use the "To Buy" column, treating the number of experience points as the number of folia required. Thus, a level 10 summa for an Art would require 55 folia, and a level 3 summa for an Ability would require 30 folia.

Those figures assume minimal illumination. Adding high-quality illumination (illuminatus) increases the number of folia required by at least 20%. A level 10 summa illuminatus for an Art would require at least 66 folia; a level 3 summa illuminatus for an Ability would require at least 36 folia.

To determine the number of gatherings in a given text, divide the total number of folia required by the average number of folia per gathering. Most texts will use quaterniones, and thus the number of folia is most frequently divided by eight. More highly-skilled scribes and binders can work with larger gatherings without impacting the quality of the text, but even such skilled craftsmen may prefer to work with quaterniones.

For example, a level 10 summa on an Art, with high-quaity illumination, requires 66 folia, or slightly more than eight quaterniones. Rather than using nine quaterniones, the scribe and binder might use a single bifolium for the ninth gathering.

For example, a level 3 summa on an Ability, with only minimal illumination, requires 30 folia, or slightly less than four quaterniones. The additional space might be used allowing some illumination, but not enough to qualify for high-quality illumination, or more marginal space might be left, to allow for glosses.

The number of gatherings determines the general thickness of a codex. While the nature of the covers used can modify that thickness, the number of gatherings is the primary factor. For the purposes of this saga rule, codices will be grouped into three overall categories of thickness: a typical codex will have around eight gatherings, ten at the most, and is referred to as a codex octonarius. A codex with fewer gatherings, perhaps four to six, would be slimmer by comparison, and thus is referred to as a codex gracilis (slim). A codex with more gatherings, from twelve to sixteen, would be thicker, or fatter, and thus is referred to as a codex crassus (fat).

Another factor to consider for the total size of a codex is the actual size of the folia used. A book with larger folia may not need as many folia for the same amount of writing. This is not always the case: sometimes larger folia are used with larger text and images, and sometimes smaller text and images are used with smaller folia. But for the purposes of this saga rule, such considerations will be blithely ignored, and a 'typical' size of text and related images will be assumed. Specific texts might have smaller folia to reflect a lower quality, or larger folia to reflect the desire of the author or binder for a large, impressive text, or the desire of older readers for larger text sizes. But such considerations are external to the purpose of this saga rule.

For the Bohemian Rhapsody Saga, folia sizes will be grouped into five general categories: Minusculus, Parvus, Solitus, Largus, and Magnus. Each size has a modifier to the number of folia required, either a multiplier for smaller sizes, or a divisor for larger sizes.

Folia Minuscula are very small, about the size of a modern paperback, or sometimes even smaller (roughly sextodecimo scale or smaller); multiply the number of folia required by at least four (x4) to reflect this much smaller size

Folia Parva are smaller than usual, about the size of a typical modern book (trade paperback or typical hardcover, or roughly octavo scale); multiply the number of folia required by two (x2) to reflect this smaller format.

Folia Solita are the most common size, about the size of an Ars Magica book, or roughly quarto scale; this is the 'standard' folium size assumed for the calculations of folia required, above.

Folia Larga are the size of a modern large 'coffee-table' book (roughly folio scale); divide the number of folia required by two (1/2) to reflect this larger format.

Folia Magna are larger than most modern books, and the sizes of such books can vary greatly; the largest surviving medieval manuscript is Codex Gigas, dating to the early 13th century; it is 36in tall and 20in wide; for folia magna, the number of folia required may be divided by four or more (1/4).

The overall size of a codex can thus be described as a combination of folia size and thickness. For example, a given text might be described as a codex solitus octonarius. This means that the folia size and thickness are both fairly typical: what might be considered a "standard" text. A codex largus crassus, by comparision, is both larger and thicker, and might contain four times the content of the "standard" text (twice the content because of the larger folia size, and twice again because of the greater number of gatherings). Such a grand text might take the place of four "standard" codices.

In contrast, a codex parvus octonarius would contain roughly half the content of a "standard" codex solitus octonarius, and a codex parvus gracilis would have still less room for content, perhaps only sufficient for a low-level textus laboris.

Abbreviations for various combinations are sometimes useful:

Note however, that the total amount of parchment required for a given amount of content is roughly the same. A codex parvus crassus would hold about the same amount of writing and illumination as a codex solitus octonarius, or a codex largus gracilis. Reasons for selecting different formats could vary greatly, from a desire for portability - or a desire to discourage portability - to the availability and quality of the hides used to make the parchment.

Larger texts require larger hides, while smaller texts may be produced from smaller hides or by dividing up a larger hide; this may be advantageous where blemishes on a hide would prevent using the entire skin, for example. Thus, larger texts are typically more expensive to produce than smaller texts, even where the size of text and illumination remain roughly the same.

Size of hides can vary somewhat, but general averages for the Bohemian Rhapsody Saga are as follows:

Sheepskin: usable area averages about 40" by 48", enough for sixteen folia largus or thirty-two folia solitus*

Lambskin: usable area averages about 35" by 20", enough for twelve folia solita (see note for sheepskin, above); folia magna are most frequently made from lambskin

Goatskin: usable area averages about 35" by 20", enough for six folia solita or twelve folia parva

Cowskin: usable area averages about 80" by 55", enough for 32 folia solita, or perhaps 16 folia larga

Calfskin: usable area averages about 50" by 45", enough for 16 folia solita, or perhaps eight folia larga; folia magna are sometimes made from calfskin

Pigskin: usable area averages about 34" by 40", enough for 6 folia larga or 12 folia solita

A "standard" codex solitus octonarius would require skins from four calves, six pigs or lambs, ten goats, or two sheep or cows.*

* there is a meme that a medieval bible required hundreds of sheep to make; this is not precisely accurate; many medieval bibles produced by monasteries were made very large, with larger text and illumination, and thus required many more hides to produce; however, it is possible to produce a bible that is smaller, and the size of a bible that most modern people would envision would not require hundreds of hides