Researchers have discovered that medieval book covers from French monasteries were made from sealskin, contrary to previous assumptions that they were crafted from deer or boar skin. A study of 43 books from a Cistercian monastery and its daughter monasteries found that the hair follicles on the covers did not match either animal, leading to DNA analysis which confirmed the use of seal skin.
The findings suggest that the Cistercians had extensive connections with global trading networks, as they used sealskin commonly used in Scandinavian countries and Ireland. However, the use of sealskin in France was unexpected due to the inland location of the monasteries and lack of evidence of seal populations on the French coast during the Middle Ages.
The researchers found that there is no written record of the purchase of sealskin at Clairvaux Abbey, but it is believed they may have had access to it through Norse trading routes. The Cistercians were likely drawn to the light grey or white colour of sealskin, which was more in line with their own tradition of using white clothing and objects.
The discovery supports the idea of a robust medieval trade network that extended beyond local sourcing, linking the Cistercians to wider economic circuits. It also highlights the importance of seal exploitation in northern Europe during the Middle Ages, where they were hunted for food, blubber, and skin.
Source: https://www.theguardian.com/books/2025/apr/10/surprise-as-sealskin-is-discovered-to-be-cover-material-of-hairy-medieval-books