New techniques that allow researchers to peer beneath the surface of old parchments has revealed ancient languages not seen since the Dark Ages. These rare tongues, only previously found on a handful of stone inscriptions, could give us an unparalleled look into works of writing long thought lost to history.

Work carried out by researchers at the Early Manuscripts Electronic Library (EMEL) in California have used modern technology to uncover previously unknown works in Caucasian Albanian, a language known from very few sources, as well as ancient medical texts by the Greek physician Hippocrates. The texts were found in the 1,500-year-old Saint Catherine’s monastery, and at some point during its long history were covered over by newer writings.

“The age of discovery is not over,” Michael Phelps, a researcher at the EMEL, told The Times. “In the 20th century, new manuscripts were discovered in caves. In the 21st century, we will apply new techniques to manuscripts that have been under our noses. We will recover lost voices from our history.”

The incredible trove of manuscripts held in the Saint Catherine’s monastery on the Sinai Peninsula, Egypt, is perhaps only rivaled by that of the Vatican. Founded on the site Moses reportedly saw the burning bush in 548 CE, it is thought to be one of the oldest working Christian monasteries in the world, as well as the oldest continually operating library.

Back in antiquity, the parchment on which texts were written was highly valued. As such, it would often reach a point where the material was worth more to the author than the text that was on it, and as such, they would wash the parchments clean before penning something else over the top.

This practice frequently occurred when monks copied out the early Bible, frequently scrubbing out original Greek manuscripts to make way for the word of Christ. With the monastery at Saint Catherine’s dating back over 1,500 years, it is thought that many ancient texts were literally rubbed out as the monks scribed away, so that while the monastery has been invaluable as a place that stored ancient knowledge, it is also responsible in part for erasing other aspects.

But now, new technology is allowing us to see through these comparatively newer written works, and recover the more ancient texts. Being called the “new golden age of discovery” by the researchers, they can take images of the manuscripts using different wavelengths of light, before feeding the data into a computer where an algorithm picks out the original text hidden below the top layer.

Now it is hoped that some ancient great texts, such as those by Aristotle, long thought lost to time, may still be hiding in plain sight.