San Zeno Wheel (Verona, c. 1455)

Commentary
San Zeno Wheel (Verona, c. 1455)
Collection: 
Map and Atlas Museum of La Jolla

Image 1: 3D model of the Wheel, rendered by Jamie Cameron with photographs by Sarah Griffin (see 'image metadata' above to find out more).
Image 2: Front of Wheel
Image 3: Back of Wheel
Image 4: Cloisters of San Zeno, Verona
Images 5: Detail of the disks 

 

The 'San Zeno Wheel' consists of three movable disks that turn on a central axis, making a device known as a 'volvelle'. Each disk is made of pine covered in vellum, with all of its content written, drawn, and painted by hand. The Wheel was originally made for the Benedictine Abbey of San Zeno in Verona. It is described as hanging on the inside wall of the cloisters by the loggia (see image 4) by a local antiquarian, Giovanni Battista Giuseppe Biancolini, in his Dei vescovi e governatori di Verona (1757).

The base disk is essentially a calendar with columns that give the duration of daylight and darkness for each day of the year. The Wheel would have therefore been used by the monks to structure their daily and annual routines. To find out how the wheel works, click on the coloured numbers on the 3D model above.

The wheel is an exceptional fifteenth-century horological device, the only one of its type to have survived. Yet certain features of the Wheel correspond to contemporary manuscript volvelles and to the liturgical calendars of larger horological devices ­– see the ‘other calendars’ unit in this paper to find out more.

 

 

Select Bibliography

G. Biancolini, Dei vescovi e governatori di Verona  (Verona, 1757) [Available online through Archive.org], pp. 21-22. 

P. Kidd, ‘A Unique Late Medieval / Early Renaissance Volvelle Astronomical Calendar’, Daniel Crouch Rare Books: Catalogue VI, ed. D. Crouch, E. Napoleone and N. Trimming (London, 2014), pp. 12-25.

S. M. Griffin: 'Synchronising the Hours: A fifteenth-century wooden volvelle from the Basilica of San Zeno, Verona,' Journal of the Warburg and Courtauld Institutes, LXXXI (2018), pp. 31-67.