The Mappa Mundi of Albi - Materials identification of an 8th century manuscript
Résumé
The Mappa mundi of Albi is one of the oldest examples of representation of the occidental world (Figure 1). The non-symbolic and non-abstract map was drawn on parchment and was probably made in the 8th century in the south of France or northern Spain. The Mappa mundi with the associated Index of winds and seas on the adjacent page, is included in a 77 folio manuscript (Ms29) conserved at the médiathèque Pierre Amalric in Albi (Tarn, France). Because it is a document of exceptional importance for global cartographic history and more widely for the history of the representation of space, the map together with the index were recorded in the UNESCO Memory of the World Register in 2015.
A detailed study was performed on the map to examine the structure of the manuscript in which it is inserted, and to characterize the different constitutive materials. Observations and physico-chemical analyses were performed from the micro to the macroscale, using mostly non-invasive analytical techniques, in order to increase the knowledge on the manufacturing technique of this document and its conservation state.
The observations evidenced the presence of three main parts in the manuscript which quires differ in their assembly and parchment quality. Hyperspectral imaging in the visible and near-infrared ranges combined with statistical data treatments, helped visualize the spatial distribution of the different components and revealed peculiar areas. Punctual spectroscopic analyses combining X-ray fluorescence, Fiber Optical Reflectance Spectroscopy (FORS), reflectance infrared and micro-Raman spectroscopies allowed the characterization of the ink, the colouring materials and organic compounds presents. For the parchment, the animal species of the skin was identified by proteomic analyses, and its conservation state examined in-situ at the micrometer scale using nonlinear optical microscopy. The results obtained from these analyses will be put in perspective with the studies led by historians on this map, as well as the existing material studies carried out on manuscripts produced in that period in Europe.