Previously unknown classical Greek mythological and medical works and other centuries-old writings have been discovered concealed on manuscripts stored in Egypt’s St. Catherine’s Monastery, organizations behind the research project — including UCLA — announced Tuesday. Also uncovered were classical scientific texts preserved only in Syriac translation, religious texts in extinct languages, an ancient Christian poem describing Old Testament figures in Homeric style and detailed illustrations of plants, buildings and people. The collaboration represents the largest effort of its kind to recover erased or obscured information from historical source material.

The discoveries were uncovered as part of the Sinai Palimpsests Project, a five-year collaboration paid for by the Arcadia Fund and carried out by the UCLA Library, the Early Manuscripts Electronic Library and the monastery, it said. The dictionary defines palimpsests as writing material, such as a manuscript, on which the original writing has been removed to make room for later writing but of which traces remain. According to project organizers:

“Spectral imaging of rare and unique ancient manuscripts in the library of St. Catherine’s Monastery on Egypt’s Sinai Peninsula has revealed treasures of inestimable scholarly and religious value, which were hidden by subsequent writing when parchment was reused. The UCLA Library and the Early Manuscripts Electronic Library have partnered with the monastery on this project, which is funded by Arcadia.”

Organizers said 74 palimpsests totaling some 6,800 pages in 10 languages contain erased layers of writing from the fifth to the 12th centuries. They are now accessible to students, scholars and the public online at sinaipalimpsests.orgUCLA Norman and Armena Powell University Librarian Ginny Steel:

“By revealing these long-hidden materials and preserving them for future generations, this project makes possible advanced research and scholarship by scholars around the world. We are extremely grateful to Arcadia for its visionary support of this international effort. Access to its collection of ancient and medieval manuscripts, considered second only to that of the Vatican Library, has often been difficult due to its remoteness and the region’s volatile political climate. In addition to revealing hidden content and making it accessible, this project has also preserved these fragile materials.”

Among the palimpsests are some of the earliest surviving copies of several Hippocratic medical treatises and a previously unknown mythological poem from ancient Hellas that mentions Zeus, Hades, Hera, Hermes and Persephone. In addition to the oldest surviving illustration in a secular Latin manuscript, illustrations include medicinal herbs, human faces and figures and portions of buildings. There are a number of double palimpsests from parchment that was re-used multiple times.

The spectral imaging process involves illuminating a manuscript with successive wavelengths of light from ultraviolet through the visible spectrum to infrared. The raw data is then processed to generate derivative images that maximize the legibility of erased content.