Reconstructing a medieval volvelle

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Within a 15th century almanac in Lambeth Palace Library (MS 454) is a set of rotatable disks sewn together at their centre and attached to a manuscript page. This calculating device is called a ‘volvelle’, a word that comes from the Latin volvere, meaning ‘to turn’. With it in hand, the medieval reader could track the movements of the Sun and Moon and use their relative positions to predict the timing of certain events, such as the lunar phases.[1]

For librarians and archivists, devices such as this – which by definition are meant to be rotated – raise difficult questions about their care. Namely, how can we balance their accessibility while preserving them for future researchers? In 2022, members of Lambeth Palace Library’s archives, conservation and reprographics teams took a closer look to learn more about the volvelle and find a solution.

Lambeth Palace Library’s volvelle (MS 454, fol. 26r)

The volvelle in MS 454, like many others that survive in 15th century almanacs, is a lunar volvelle, named so because when the top disk is turned a circular aperture reveals the shape of a shining, golden Moon that waxes and wanes according to the positioning of the disks. Although it is similar to other volvelles of this kind (see another 15th century English example from the British Library below), our inspection revealed unique features that needed careful consideration before making any decisions about its handling.

First, while there are four functional parts to the volvelle (each of which can be viewed separately here), these together are made up from eight separate layers of parchment. Some volvelles have additional pointers to carry out other calculations, such as the below example in Chetham’s Library which has seven arms that relate to the planets. The extra disks in our volvelle are instead for reinforcement. By layering the parchment components on top of one another, the disks are made more durable.[2]  

Left: Volvelle in LPL, MS 454, showing the eight separate disks (the calendar disk is also reinforced)
Right: Manchester, Chetham’s Library, MS A.4.99 (England, 15th century)

Second, the movement of the disks in MS 454 is limited. Most volvelles are sewn in such a way that the disks can (with care) be turned in a full circle. The method of the disks’ attachment in MS 454, however, means they cannot move beyond a certain point without snapping the string or, worse yet and more likely, damaging the parchment. This is probably due to the replacement of the thread, which seems to be a modern intervention.

We therefore needed to find a way that readers could better understand how the volvelle worked without manually turning the disks. Our team came up with two solutions.

  1. A facsimile. Anyone who comes to look at MS 454 will be offered use of a facsimile where the disks fully turn.
  2. An animation that shows each of the disks moving independently (see below).

In both, the shape of the Moon (seen through the circular window) changes according to the positioning of the disks. Capturing this wonderful feature presented a challenge. In order to show exactly how the shape of the Moon changes we needed to recreate the appearance of the middle component—the ‘solar disk’—which is sewn tightly between two other disks. To do this without taking the volvelle apart required the combination of a few different photography techniques, which Susie Hilmi (creator of the animation) explains on her website: Susie Hilmi – Medieval Volvelle – Project at Lambeth Palace Library (myportfolio.com)

The asymmetrical ‘heart’

The outcome is not only a fun and functional animation, but also a rare glimpse at the appearance of the ‘heart’ of a solar disk – the part of a lunar volvelle used to simulate the phases of the Moon. Whereas we know what printed versions of these disks look like as many were made for the reader to assemble themselves (see examples here), those of manuscript volvelles are only ever seen if the device is disassembled or damaged, as shown by the example below. Through a combination of techniques, we discovered an unexpected asymmetrically to the ‘heart’ of Lambeth’s volvelle, revealing new insights into the manuscript that we would not have gained by inferring its appearance from other examples.[3]

Left: Solar disk of MS 454 with asymmetrical ‘heart’
Right: Volvelle without its top disk in British Library, Egerton MS 2572, f. 51r (© The British Library Board) 

Resources (available online)

Susie Hilmi, ‘Medieval Volvelle – Project at Lambeth Palace Library’ (2022): https://susiehilmi36ae.myportfolio.com/projects

Suzanne Karr Schmidt, ‘Flaps, Volvelles, and Vellum in Pre-Modern Movable Manuscript and Print’, in Proceedings of POP-APP. International Conference on the description, conservation and use of movable books (2022), available online: https://doi.org/10.57579/2022JIB001SKS

Timothy J. Mitchell, Binding the Heavens: Deconstructing the Lunar Volvelle (2018):http://astrolabeproject.com/downloads/volvelle/deconstructing_the_lunar_volvelle.pdf
The project includes an interactive volvelle simulation : www.astrolabeproject.com/sim/lunarvolvelle/sim.html

Sarah Werner, ‘Constructing volvelles’, Folger Shakespeare Library website (2014): www.folger.edu/blogs/collation/constructing-volvelles/

Other volvelles shown

Like what you see here? Why not  take a look at Newberry Library’s exhibition ‘Pop-Up Books through the Ages‘ (March 21—July 15, 2023)

[1] For different uses of the lunar volvelle, see Timothy J. Mitchell, Binding the Heavens: Deconstructing the Lunar Volvelle (2018): http://astrolabeproject.com/downloads/volvelle/deconstructing_the_lunar_volvelle.pdf

[2] For other examples of volvelle reinforcement using parchment, see Suzanne Karr Schmidt, ‘Flaps, Volvelles, and Vellum in Pre-Modern Movable Manuscript and Print’, in Proceedings of POP-APP. International Conference on the description, conservation and use of movable books (2022), available online: https://doi.org/10.57579/2022JIB001SKS

[3] For the two shapes used to simulate the phases of the Moon in lunar volvelles, see Mitchell, Binding the Heavens: Deconstructing the Lunar Volvelle, p. 10.