A multi-technical method for the taxonomic identification and production history of three medieval gilt leathers from the Palacio de Viana in Córdoba

Gilt leather was an artistic representation made on skin that became widely popular in the late 15th century and, especially, in the first half of the 16th century. It was a carved leather whose main decoration was gilding and painting, often with additional engravings and embossing. Its elitist character and the social recognition it acquired turned this object into a symbol of cultural identity. Nevertheless, understanding the complex production techniques requires an overview not limited to written sources, especially with regard to the nature of the hide. We applied Zooarchaeology by Mass Spectrometry (ZooMS) using matrix-assisted laser desorption/ionisation trapped ion mobility time-of-flight mass spectrometry (MALDI-timsTOF) to three gilt leathers from the Palacio de Viana leather collection (Córdoba, Spain). Using minimal amounts of sample, the three objects were established to derive from sheepskin. This technique also allowed us to estimate the peptide deamidation levels, found to be higher than those estimated in parchment. This likely reflects the aggressive chemical treatment of leather and its preservation history. The combination with a scanning electron microscope analysis fitted with an energy-dispersive spectroscopy (SEM-EDS) detector contributes to the reconstruction of their production history.