The discovery of hidden medieval manuscript fragments inside early modern book bindings has long been a challenge for historians and scholars. Many medieval texts were lost over the centuries as bookbinders in the 16th and 17th centuries repurposed older manuscripts to reinforce new book bindings. These fragments, often cut into strips and pasted inside the spines and covers of books, remained invisible for centuries—concealed within the very structure of early modern books. Now, thanks to an innovative new approach using an endoscopic camera, researchers have found a way to reveal these hidden treasures without damaging the books themselves.
This groundbreaking work was conducted as part of the project “FragmEndoscopy: An Innovative Way to Discover Hidden Heritage inside Early Modern Book Bindings,” led by Thijs Porck, an associate professor of medieval English at Leiden University. His research offers an entirely new way to examine the interiors of book bindings without invasive methods. By inserting an endoscopic camera into the narrow gaps within book spines, researchers were able to record images of medieval fragments that have remained unseen for hundreds of years.
The Hidden History of Reused Manuscripts in Book Bindings
The practice of recycling old manuscripts for bookbinding materials was common in the early modern period. Parchment, the primary material used for medieval manuscripts, was expensive and labor-intensive to produce. Rather than discarding older manuscripts that were no longer in use, bookbinders cut them into strips and used them to reinforce the bindings of newly printed books. This method of reinforcement made books more durable, but it also meant that countless medieval texts—some of which may have been rare or even unique—were dismembered and hidden within the spines of newer books.
This process was especially common in the 16th and 17th centuries when the transition from manuscript culture to printed books led to a decline in the perceived value of handwritten texts. As the demand for printed books increased, medieval manuscripts were frequently seen as obsolete and were often repurposed in ways that concealed their content. This means that many books from this period contain fragments of lost medieval texts—hidden away and forgotten for centuries.
Using an Endoscopic Camera to Reveal Hidden Texts
Until now, accessing these fragments without damaging the books has been a major challenge. Traditional methods, such as X-ray imaging, have been expensive, time-consuming, and sometimes ineffective in revealing clear details of the hidden texts. However, in the FragmEndoscopy project, researchers used an endoscopic camera originally designed for inspecting gun barrels.
This specialized camera, with its small diameter and built-in mirrors, allowed researchers to perform a kind of “keyhole surgery” on books, inserting the device into tiny gaps within the book bindings to capture images of the hidden fragments. The process was non-invasive, meaning the books remained intact while still allowing researchers to explore their internal structures.
Professor Porck, along with student assistant Iris van Kuijk, tested this method on several books housed in Leiden University Library and the Noord-Hollands Archief in Haarlem. They recorded videos of the books’ interiors and then compiled screenshots from these videos, stitching them together to create full images of the hidden fragments. This approach allowed them to reconstruct the appearance of these medieval texts without physically removing them from the bindings.
Discovering Medieval Music and Middle Dutch Manuscripts
The results of the FragmEndoscopy project have been remarkable. The team successfully identified various medieval manuscript fragments, including Middle Dutch texts and a 14th-century musical fragment complete with musical notation. These discoveries provide valuable insights into medieval literature, music, and book production practices.
One of the key advantages of this method is its cost-effectiveness and efficiency. Previous techniques for uncovering hidden fragments relied on X-rays and complex scanning technologies, requiring expensive equipment and lengthy analyses. In contrast, the endoscopic camera used in this study cost less than 600 euros and could capture images within minutes, while assembling the complete images took only a few hours. This makes the method highly accessible and practical for libraries, archives, and researchers around the world.
A New Future for Book History Research
The FragmEndoscopy technique represents a major breakthrough in the study of medieval manuscripts and book history. By providing a non-invasive, affordable, and efficient method to explore the insides of book bindings, this approach opens new possibilities for uncovering lost texts. Many medieval manuscripts once thought to be lost forever may still survive—hidden within the bindings of early modern books in libraries and archives worldwide.
Future research could apply this method to even more historical collections, potentially revealing forgotten literary works, legal texts, religious manuscripts, and musical compositions. Additionally, the success of FragmEndoscopy could inspire further technological innovations for examining hidden historical materials without damaging them.
By combining modern technology with historical research, scholars are now able to reclaim fragments of the past that were once thought to be lost. The work of Porck and his team demonstrates how new techniques can revolutionize our understanding of medieval and early modern book culture, shedding light on hidden stories that have been trapped within book bindings for centuries.
More information: Thijs Porck et al, Medieval Fragments Revealed with FragmEndoscopy, Fragmentology (2025). DOI: 10.24446/h9ht