Evagations Diagrams in Medieval Computus

Resumo

Evagations diagrams are visualisations of patterns of cyclical movements of celestial objects (that could be measured by observation and calculated using different methods, but which were difficult to grasp purely from texts), that developed as a medieval visual tradition. Its design was intended to assist the reader in making sense of complex information (presented in circulating manuscripts) through an imagetic translation of those phenomena – that are otherwise only visible through long-term sky observations. Their frequent presence in computus turned them into graphical receptacles (or templates) for different concepts related to the paths of planets, such as elongations, altitudes, latitudes and longitudes, which were key to understanding how the world worked, and to determining the usefulness of that knowledge.

Starting with manuscript Bern Cod. 347, a composite manuscript produced in the second half of the ninth century in the region of Auxerre, this article will provide an overview on the transmission of diagrams of latitudes (planetary wanderings in relation to the ecliptic of the sun through the course of the zodiac) in manuscripts assembled and copied mainly for Benedictine schools, in the Carolingian and post-Carolingian periods; exploring them as pictorial representations of an established visual concept, made up of a mixture of real and imaginary data, and will inquire about the ways in which these compositions were used to convey cosmographical knowledge.

Keywords: Visual Representation; Natural Philosophy; Computus; Cosmography; Latitudes.

DOI: https://doi.org/10.21747/21836884/med41a34