Una classificazione delle pavimentazioni geometriche realizzate dai Cosmati

Flagg Moran, Judith ; Williams, Kim

Bollettino della Unione matematica italiana, Série 8, 7A (2004) no. 1, pp. 17-47

Résumé

While geometric decoration is found in all cultures and all ages, the Cosmati, a group of related families of marble workers of the late Middle Ages, created a decorative style that is unique in the genre. Using a four-colour palette of red, green, white and yellow tiles in a variety of geometric shapes such as squares, triangles, circles, rhombuses, hexagons, and octagons, the Cosmati decorated the pavements, altars, and facades of over 100 churches. Few attempts have been made to catalog the individual geometric patterns of the Cosmati, but such a catalog would be of great value to art and architecture historians and to those studying other kinds of geometric decoration, such as Islamic or Native Americans. In order to create a catalog, it is first necessary to provide a standard for identifying and classifying the patterns. Such a classification system must provide categories that are mutually exclusive, exhaustive, described in objective terminology, usable by non-specialists, and identified by a clear nomenclature. Based upon several years spent studying a specific group of Cosmati patterns, the authors have devised an efficient system, described in the present paper, that meets all the requirements to identify and classify patterns so that a catalogue can be created. The classification system is based on a series of tree diagrams related to the underlying grid structure for the individual patterns and involves series of questions in order to identify patterns correctly according to type. The correct classification and subsequent catalogue will enable the second part of the research to go forward, which is to understand the shape grammar, that is, the set of aesthetic rules for combining geometric shapes to create patterns, in order to understand better how these medieval artisans designed and created their unique style.