X-Rays Reveal Writing on Ancient Scrolls from Mt. Vesuvius Eruption

Photo courtesy University of Kentucky

Mount Vesuvius erupted in 79 AD destroying the wealthy Roman resort town of Herculaneum along with the better known Pompeii. Beginning in 1738 Charles of Bourbon (Charles III of Spain) sent archaeological teams to Pompeii and Herculaneum to dig up artifacts after Roman items were discovered by well diggers and treasure hunters. In 1752, the team discovered their first scroll and in 1754 they had discovered an entire library of scrolls inside the ancient villa. They uncovered roughly 800 charred scrolls from the library now called "Villa de Papyri" under more than 50 feet (15 meters) of ash. 

As soon as the scrolls were discovered people wanted to know what was written on them. Over the centuries, various techniques were devised to unroll the scrolls, but they usually ended up destroying the brittle papyrus. Historians have tried many methods for reading the damaged scrolls. "They poured mercury on them, they soaked them in rosewater — all kinds of crazy stuff," said Jennifer Sheridan Moss, a papyrologist at Wayne State University in Detroit. Even the most careful unrolling can lead to their destruction. A clever unrolling machine designed by a monk in the 1700s, was fairly successful, but most wound up damaging the fragile documents.

Of the 1,814 scrolls unearthed, around 300 have been deciphered. From those scrolls historians determined that the library was filled mainly with writings on Epicurean philosophy with a large collection of works from a prolific writer named Philodemus.

Photo courtesy Salvatore Laporta/AP

Conventional x-rays of the rolled-up Herculaneum scrolls don't reveal anything because the Herculaneum scrolls presented a unique challenge: papyrus was burnt and the text was written with black, carbon-based ink. Common X-ray techniques could not detect the pattern variations between the ink and the papyrus, so researchers tried an x-ray technique which reads the text through the rolled-up papyrus by discerning charcoal ink from charred papyrus. 

 This new approach, called X-ray phase-contrast tomography (XPCT), builds a higher-definition image by detecting the slight relief between the letters and the papyrus. The letters rise just one hundred microns above the papyrus, but that’s enough to build a clearer picture than any other technique. Similar to a medical CT scan, the new process produced a three-dimensional view of the folded, compressed interior of the charred scroll. Unlike regular x-rays, the method can distinguish the charcoal ink from the surface of the charred papyrus.

The scrolls’ small sizes and numerous folds make it difficult to focus on every letter or gauge the letter’s orientation. But what’s important is that researchers proved that you could peek inside these ancient scrolls without destroying them.

Image by Vito Mocella/ Nature Communications

Studying the interior surface of the scroll, the researchers demonstrated they were able to read letters, a few microns thick, written on the papyrus long ago. A first effort deciphered 24 letters used in ancient Greek, the language of philosophy in the Roman world.

 

It is going to be a while before the scrolls are completely interpreted. However, researchers’ new technique is an encouraging start. Using XPCT, researchers examined two scrolls and could clearly see letters that formed short phrases such as “would fall” or “to deny,” but not much more. Daniel Delattre of the Institute for the Research and History of Texts in Paris examined the handwriting of the few letters and words that the team was able to recover. He compared the handwriting to that in other Herculaneum scrolls, and found a match with a scribe writing in the first century bc. Given that scribe’s activity in other scrolls, the new text is likely to be a copy of writing by the philosopher and poet Philodemus.

 

Villa de Papyri

Long ago archaeologists gave up on opening the texts to spare the culturally important artifacts, but this imaging technique allows researchers to see what’s written inside, without ever opening the delicate artifacts. The researchers hope that the method leads to a non-destructive way to investigate more of Herculaneum's charred papyri, which in turn will reopen consideration of more excavations at the Villa de Papyri. 

Scholars have long pondered the possibility of another library buried deeper beneath its ruins because most Roman libraries held the Greek treatises in one section and Latin books in another. If they do find the hidden library, this new technique could become very useful.