Saint Catherine's Monastery, a sacred Christian site nestled in the shadow of Mount Sinai, is home to one of the world's oldest continuously used libraries. Thousands of manuscripts and books are kept there -- some of which contain hidden treasures. An anonymous reader shares a report: Now, a team of researchers is using new technology to uncover texts that were erased and written over by the monks who lived and worked at the monastery. Many of these original texts were written in languages well known to researchers -- Latin, Greek, Arabic -- but others were inscribed in long-lost languages that are rarely seen in the historical record. Manuscripts with multiple layers of writing are known as palimpsests, and there are about 130 of them at St. Catherine's Monastery, according to the website of the Early Manuscript Electronic Library, which has been leading the initiative to uncover the original texts. With the rise of Islam in the 7th century, Christian sites in the Sinai Desert began to disappear, and Saint Catherine's found itself in relative isolation. Monks turned to reusing older parchments when supplies at the monastery ran scarce. To uncover the palimpsests' secret texts, researchers photographed thousands of pages multiple times, illuminating each page with different-colored lights. They also photographed the pages with light shining onto them from behind, or from an oblique angle, which helped "highlight tiny bumps and depressions in the surface," Gray writes. They then fed the information into a computer algorithm, which is able to distinguish the more recent texts from the originals.