Centuries-old books — with hairy covers — were bound with animal skin in France
At the end of the ninth century, a group of Roman Catholic monks in France struck out on their own.
Dissatisfied with the rules of the Benedictine abbey they called home, they created the Cistercian rule and order in 1098 and grew to be known as the “White Monks.”
The monks curated a vast manuscript and book collection at the Library of Clairvaux Abbey, a site in Champagne, France, founded in 1115. The group of 12th- and 13th-century works expanded to more than 1,000 volumes at the beginning of the 14th century.
“Today, the collection represents a remarkable corpus of 1450 surviving medieval books, with approximately 50% still in their original bindings. Of these, 168 are Romanesque bindings from the 12th to 14th century, with 28 almost intact,” researchers said in a study published April 9 in the peer-reviewed journal Royal Society Open Science.
But unlike other medieval libraries, the Clairvaux Romanesque manuscripts have an additional second cover, called a chemise, according to the study. The cover isn’t made from fabric or paper, but rather an “atypical” leather with hair still attached.
“In historical library catalogues, the skin is described as being made from either boar or deer,” researchers said. “However, upon closer examination, the distribution of the hair follicles on the covers was found to differ from that of either animal.”
Now, analysis of the covers reveals the distant lands — and animals — where the chemises originate.
Researchers used a process called electrostatic zooarchaeology to examine seven skin bindings and conducted genetic analysis on another nine books, according to the study.
“Having identified this specific type of binding, characterized by a furry skin chemise, further research was conducted in other libraries,” researchers said. An additional 23 books were found in medieval libraries in France, England and Belgium.
The study revealed the fur didn’t belong to boars or deer, but rather pinnipeds, or seals and walruses.
More specifically, the DNA still contained in the book binding allowed researchers to narrow their search to harbor and harp seal populations from Scandinavia, Scotland, Iceland and Greenland, far from the land-locked region of Champagne.
“The skins were found on manuscripts that were produced in areas that are situated on 13th-century European trading routes. Clairvaux is located near a land trading route, and was connected to the Champagne fairs, to which Clairvaux was close (and we know that the monks of Clairvaux were allowed to attend,” researchers said.
The samples were also found near Norse trading routes established after Norse people arrived in Greenland in the 9th century and traded walrus ivory and fur with Europe, often in the form of gifts and tithes, or payments to the church, according to the study.
“Contrary to the prevailing assumption that books were crafted from locally sourced materials, it appears that the Cistercians were deeply embedded in a global trading network, acquiring skins through extensive trade exchanges,” researchers said.
The choice to use these seal skins in particular may have stemmed from their color, according to the study.
While the chemises appear brown and faded today, the skins originally would have been white, aligning with the token color of the “white monks,” as brown was used by the Benedictine order they left behind, according to the study.
As the skin became more brittle, the hair fell out and the fatty layer beneath began to show more through the years, the white color faded, researchers said.
Other than the color, the reason why the monks chose to bind their books in seal skin remains a mystery.
“We have no written records to explain why monks chose to cover these manuscripts in sealskin, nor can we determine if these covers were a sign of particular value or symbolism,” researchers said. “The seal was rarely depicted in medieval art and did not hold a place in heraldry, which developed at that time. This lack of representation might have contributed to a detachment from the animal’s true identity, making it difficult for contemporaries to recognize sealskin as a specific material.”
The Clairvaux Abbey is in northwestern France, about 150-mile drive southeast from Paris.
The research team includes Élodie Lévêque, Matthew D. Teasdale, Sarah Fiddyment, Maiken Hemme Bro-Jørgensen, Luke Spindler, Ruairidh Macleod, François Bougard, Morten Tange Olsen and Matthew Collins.
This story was originally published April 9, 2025 at 1:43 PM with the headline "Centuries-old books — with hairy covers — were bound with animal skin in France."
