A sealed scroll from the Roman town of Herculaneum, which was destroyed by Mount Vesuvius' eruption nearly 2,000 years ago, has finally given up its secrets, thanks to a combination of machine learning and high-resolution CT scans. In 2023, researchers managed to decipher a few words from among the char and ash that make up the bulk of the scrolls. Some of those same prize-winning researchers recovered more passages from one of the scrolls, PHerc.Paris.4, netting them the $700,000 grand prize from the Vesuvius Challenge contest in early 2024. Fast forward two more years, and those grand prize winners are now part of the Vesuvius Challenge team that managed to read the surviving portion of a rolled scroll end-to-end, as the VC team shared in a Thursday announcement and detailed in an accompanying paper [PDF]. According to the research paper, the ability to make out the entirety of the scroll was thanks to high-resolution phase-contrast X-ray microtomography performed at the European Synchrotron Radiation Facility in France - an improved imaging technique over prior methods used to capture prior images that were analyzed in the prize competition. That wasn’t all, though: They say that much of their work succeeded because of a new "workflow" they developed to scan scrolls, detect ink on charred papyrus, virtually "unroll" the scrolls by modeling their deformed surfaces, and preserve those surfaces digitally, allowing machine learning models to identify letters across an entire scroll rather than just isolated patches. "The key transition marked by the present work is therefore from exceptional local recovery to systematic scroll-scale recovery," the team wrote. In other words, provided they can account for the particularities of the hundreds of sealed scrolls recovered from Herculaneum's Villa of the Papyri, the world's only surviving intact library from antiquity, this could mark the beginning of an explosion in new material for historians. So, what did it say? PHerc.Paris.4 wasn’t at the center of this breakthrough either, though they did have some exciting news to share on that front that we’ll get to. Instead, the breakthrough centered on PHerc. 1667, a previously unread rolled scroll whose preserved text was read continuously from end to end for the first time. The work appears to be a treatise on Stoic philosophy focused on ethics - a favorite subject of Zeno, Marcus Aurelius, Epictetus, and their intellectual fellows. “Having certainly strained ourselves to the utmost through research and learning, we will no longer be inferior to them in any respect,” a passage from the latter part of the scroll reads, “accomplishing in like manner the things that befit them and possessing the same practical wisdom as they.” Quite a fitting bit of ancient wisdom to be the first to see the light of the modern world. While the team digitally unrolled the scroll, detected its ink, and transcribed the preserved text from end to end, portions of the original PHerc. 1667 were lost long ago during earlier attempts to physically open the scroll, before archaeologists had access to sophisticated X-ray imaging and AI-assisted analysis. “Earlier attempts to open it by hand — in the nineteenth century, and again in 1969 and the 1980s — destroyed its outer layers,” the Vesuvius Challenge team said, noting that only an 8 cm-high core remains of the original scroll, which originally measured between 19 and 24 cm in height when standing upright. Nonetheless, “it is the first time the preserved text of a rolled Herculaneum scroll has been read continuously, end to end, rather than in isolated words or patches,” the team said. In addition to the full reveal of what’s left of PHerc.1667, the team also managed to pick out some information from a couple of other scrolls using their new workflow. One, PHerc.139, was determined to be a copy of book eight of epicurean philosopher Philodemus’ treatise On Gods, meaning scholars can expect to know what they’re looking at once the scroll is fully digitally unrolled. The second concerns, as mentioned above, PHerc.Paris.4. The new higher-resolution images taken for this latest experiment make the words on the scroll directly visible for the first time, meaning that there’s no need to rely on algorithmic detection of individual words and phrases from CT scans. Most crucially, the new scans of Paris.4 perfectly matched what the grand prize team made out several years ago, providing independent confirmation that the prize went to the right team. There are still challenges to meet in unwrapping and deciphering the rest of the ancient library, with the team calling out geometric challenges in surface prediction that can render an unrolled scan unreadable, and radiometric challenges that make ink identification difficult, as ancient recipes were inconsistent. Still, it’s a massive leap forward and the team believes the X-ray and machine learning workflow they’ve developed is ready to scale. “The thoughts of the ancient world, sealed in darkness for two millennia, are coming back into the light — a whole scroll at a time,” the Vesuvius Challenge team said. I, for one, can’t wait to see what ancient secrets they discover next. ®
