English folding almanac in Latin. MS.8932. Wellcome Library, 2014.

In the world of medieval English bookmaking, 15th century saw emergence of a physician's folded almanac. The book, which was produced to be carried around; where each page expanded individually to allow the medical practitioner access essential information on stars, saints and signs of Zodiac.

English folding almanac in Latin. MS.8932. Wellcome Library, 2014.

Folded almanac belongs to the late medieval period, when astrology, science and magic coexisted in medicine. Almanacs were utilitarian tools, which helped physicians check the alignments of starts before making a diagnosis or commencing a treatment. They contained calendar (with saints' days), charts as well as diagram of Zodiac Man, which indicated the parts of the body as they were ruled by the signs of Zodiac.

English folding almanac in Latin. MS.8932. Wellcome Library, 2014.

The almanacs must have been abundant in the 15th century. By the end of the 1500s, physicians across Europe were required by law to calculate the position of the moon before carrying out complicated medical procedures, such as surgery or bleeding(2).

English folding almanac in Latin. MS.8932. Wellcome Library, 2014.

By the end of the 1500s, physicians across Europe were required by law to calculate the position of the moon before carrying out complicated medical procedures, such as surgery or bleeding. - See more at: http://www.bl.uk/the-middle-ages/articles/medicine-diagnosis-and-treatment-in-the-middle-ages#sthash.1o8erWVQ.dpuf

The almanacs had a "best before" date - the astronomical and astrological data was only calculated for a period of about ten years. A physician could only safely consult the manuscript during those years, after which he would need an updated version of the calculations (4). It is thought(4), that this is the reason why so few of them survived to this day.

English folding almanac in Latin. MS.8932. Wellcome Library, 2014.

Almanacs - like contemporary books - were portable objects: they were produced to be carried around, often hung on the belt. They were built out of individual sheets of parchment, which were folded and sewn together to create a fan-like structure that allowed each leaf to be unfolded individually(1) - not unlike maps. Almanacs’ practical function suggests that they were both ephemeral – readily discarded and replaced – and relatively inexpensive to produce with (often) crude illustrations(3). The more lavishly decorated ones (as the one from Wellcome Library shown here), suggest that their ownership extended to the wealthier patrons, who might have not necessarily practiced medicine.

English folding almanac in Latin. MS.8932. Wellcome Library, 2014.

As seen from the images, the structure is similar to the map fold: the book is contained in a small case, but each page can be expanded into the space well beyond the size of the book. My brief online research suggests, that there are a few variants of the fold, including a type of concerina. A wonderful blog post by Teffania shows her attempts to recreate the almanac structure.