‘Invisible message’ on 15th-century medieval manuscript discovered by college students

ROCHESTER, N.Y. — Uncovering a medieval document in mint condition is an exciting day for any historian. Now imagine discovering that document has an invisible message hidden in its paper, waiting to be found for the last 600 years. That’s exactly what has happened at the Rochester Institute of Technology. A group of college students has created an imaging system that unearthed never-before-seen text on a 15th-century manuscript.

Hidden Text Medieval Paper
The image on the left shows the document as it appears in visible light. The image on the right was produced by the student-built imaging system. (Credit: Rochester Institute of Technology)

Using ultraviolet-fluorescence imaging, students revealed a manuscript leaf from the school’s Cary Graphic Arts Collection is in fact a palimpsest. This document, written on parchment, contains several layers of writing. In its time, parchment paper was an expensive product to make, which meant they were often scraped clean and re-used. Although the naked eye can’t spot the previous writings, the chemical residue still remains.

“Using our system, we borrowed several parchments from the Cary Collection here at RIT and when we put one of them under the UV light, it showed this amazing dark French cursive underneath,” imaging science student Zoë LaLena explains in a university release. “This was amazing because this document has been in the Cary Collection for about a decade now and no one noticed. And because it’s also from the Ege Collection, in which there’s 30 other known pages from this book, it’s really fascinating that the 29 other pages we know the location of have the potential to also be palimpsests.”

COVID can’t slow down science

Students UV light
A team of students, Including Lisa Enochs, left, created the imaging system for their Innovative Freshman Experience class. (Credit: Gabrielle Plucknette-DeVito)

Nineteen students helped to construct the imaging system as part of a year-long course at RIT’s Chester F. Carlson Center for Imaging Science. The team was forced to stop work in March when schools switched to remote learning due to the coronavirus pandemic. Luckily, a donation from an RIT alumni allowed three students to keep working through the summer.

LaLena, Lisa Enochs, and Malcom Zale completed the system in the fall and started examining pieces from the Cary Collection. Their discovery has stunned the collection’s curator, Steven Galbraith, who says these ancient leaves have been carefully analyzed by scholars and no one ever knew the writing was there. Until now, these documents have never been placed under UV light.

More hidden messages may be out there

This palimpsest comes from the Otto Ege collection, which the historian and collector assembled from damaged and incomplete manuscripts. They were eventually sold to libraries and historical collections across North America. The Cary Collection curator says this opens up the possibility more relics have the same hidden texts on them.

“The students have supplied incredibly important information about at least two of our manuscript leaves here in the collection and in a sense have discovered two texts that we didn’t know were in the collection,” Galbraith adds. “Now we have to figure out what those texts are and that’s the power of spectral imaging in cultural institutions. To fully understand our own collections, we need to know the depth of our collections, and imaging science helps reveal all of that to us.”

The students have already examined another document from the Ege collection which also turned out to be a palimpsest. That manuscript is part of a collection at the Buffalo and Erie County Public Library. As the students gather more pieces of the puzzle, researchers will soon be able to figure out what information these 600-year-old manuscripts are hiding.

The students will be presenting their discovery at the 2021 International Congress on Medieval Studies.