Apr 24, 2018

The Construction and Function of a Physician’s Folding Almanac: British Library Harley MS 937

Julie Maseka

Leather case of Harley MS 937
Harley MS 937 is plainly catalogued by the British Library as a physician's folding almanac; however, this description fails to capture the uniqueness of this seemingly simple, yet intriguing, manuscript. In general, folded almanacs contain “calendrical, astrological, and medical elements” thought to have been used by both medical practitioners and laypeople (Carey, "What is the Folded Almanac?" 482). Harley MS 937 stands out in this category of manuscripts due to its distinct construction and interesting textual content. The manuscript is folded and enclosed in a leather pouch bound with a braided string, which offers both protection and portability. The text is in English vernacular, although Latin would be commonly expected of astrological-medical documents of this time period. While the text poses questions about the owner(s) of the manuscript and how they may have practically used it, this post will focus on how the physical format of Harley MS 937 influences its transportability and readability, leaving the discussion of the intended owner and the manuscript's application in medieval daily life for a later date.

The folded construction of the Harley MS 937 is vastly different than the format of medieval codexes, which creates some distinct challenges in regards to its function. The dimensions of Harley MS 937 when collapsed are 145 mm by 45 mm, allowing it to fit comfortably in the palm of a hand (Catalogue, "Detailed Record for Harley 937"). It has ten folios that fold in half vertically and then in three ways horizontally. The pages are bound together at the bottom edge as opposed to the middle of the fold, creating an opening that is vertical, not horizontal. This fragile design choice creates the risk of individual leaves being easily ripped out or falling out; additionally, the flimsy construction of the binding makes it vulnerable to disintegration with frequent use. Practically speaking, the act of unfolding and refolding is a bit clumsy, as the pages are loosely bound instead of neatly sewn together in a quire. The format of a folded almanac does not lend itself to one-handed reading or flipping of pages. Compared to codexes, this inefficiency limits the functionality of the folded almanac in situations where a quick reference is needed and only one hand is available. Opening the almanac with a single hand is nearly impossible; this limitation is likely a large part of the reason why its format was not widely adopted for other manuscripts.
Illumination in Harley MS 937, fol. 4v

Reading and retrieving information from Harley MS 937 is a unique practice due to its interesting layout. The page design of this manuscript and that of other folded almanacs suggests that the goal in reading them is quick retrieval of information. This is demonstrated by the clear headings and neat ruling, which indicate “their highly functional purpose.” To be a useful reference tool for physicians and laypeople, folded almanacs contain information “to diagnose and prognosticate, as well as to obtain information about the phases of the moon, religious feasts and other key moments in the calendar” (Brenner, "Enigma").

To read the text of Harley MS 937, the pages must be unfolded by opening the two flaps and flipping up each leaf to create an opening. The text is oriented for vertical reading, which is ideal for the long columns of the kalens. Based on the medieval calendar of John Somer, these kalens begin in order with January and conclude with December (Catalogue). Locating specific dates within the month is straightforward; however, navigating the text when desired information is not chronological can be time-consuming. For instance, searching for the date of a specific saint’s day when the month is unknown requires the user to flip every leaf and search. Although not a huge disadvantage in a manuscript with only ten pages, this is a slight inconvenience and proves the format of folded almanacs functions best when information is sequential.

Vertical view of Harley MS 937
The compact design of Harley MS 937 allows the manuscript to be enclosed in a flexible vellum pouch, protecting it from the elements and allowing for easy transportation. Water damage is visible on the exterior folded portions of the manuscript and the interior displays some browning (specifically folios 1r and 10r), but the document is otherwise remarkably well-preserved. The rubrication and illumination of initial letters remains extremely vivid, suggesting that the protective cover of the manuscript has done its job shielding the document for centuries. The absence of wood covers and heavy leather bindings makes the folded almanac light and portable — features that the normal medieval codex cannot compete with. Additionally, in comparison to rolls and scrolls, the folded almanac format is less likely to be crushed. Therefore, the folded almanac as a whole is better protected and lighter than any other form of manuscript.

The pouch of the folded almanac has led to the assumption that these documents are meant to hang from the body, increasing their functionality through portability. Harley MS 937 and all other folded almanacs fall into a general category of vade mecum (“come with me”) manuscripts. This term can be applied to “any small, portable notebook or manuscript” (Carey, "What is the Folded Almanac?" 485). Harley MS 937’s pouch has a short braided cord knotted twice into a loop that could easily be attached to a belt. Similar to girdle books, which are codexes bound with excess leather gathered into a knot and tucked into the belt of the wearer, the folded almanac's pouch “appears to have been designed to hang from the belt” (Carey 482). However, it is possible that the cord of Harley MS 937 may have been used to secure it to another piece of clothing. Carey argues that “we cannot be certain how any particular user of the folded almanac chose to wear or carry it” because of the lack of pictorial evidence ("What is the Folded Almanac?" 489). Despite the illustrations portraying “saints and clerics wearing the continental girdle book, physicians do not appear to have been depicted in a similar pose” with folded almanacs (Carey, “Astrological Medicine” 493). Medieval physicians are illustrated with pouches hanging from their waist that are thought to contain money; however, it is possible that this accessory is “not a purse for money, but a bag or pouch into which a medieval physician put the book which helped him to make a quick decision about the treatment of a patient” (Talbot 214). Ultimately, the compact form of the folded almanac makes it ideal for transporting information.


Folded almanacs are eccentric and amusing manuscripts that offer insights into the reading practices of medieval people, including their desire to transport information. Despite the format's numerous drawbacks in comparison with medieval codexes, such as low searchability and inefficient construction, the folded almanac is practical for the medieval person who desires the convenience of wearing a small, lightweight manuscript on his or her person. The differences between individual folded almanacs highlight the varying interests of physicians and laypeople in the area of astrological medicine: a topic which will be explored in a follow-up post.

Works Cited

Brenner, Elma. “The Enigma of the Medieval Almanac.” Wellcome Library, 2014,

Catalogue of Illuminated Manuscripts. “Detailed record for Harley 937.” British Library,

Carey, Hilary. “Astrological Medicine and the Medieval English Folded Almanac.” Social History of Medicine, vol. 17, no. 3, 2004, pp. 345-363.

---. “What is the Folded Almanac?” Social History of Medicine, vol. 16, no. 3, 2003, pp. 481-509.

Talbot, C. H. “A Medieval Physician’s Vade Mecum.” Journal of the History of Medicine and Allied Science, vol. 16, no. 3, 1961, pp. 213-233.

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