Herculaneum papyri: reading without unrolling

Sun, 04 Oct 2026 00:00:00 +0000

Fragments of papyrus PHerc. 1521, held by the British Library. Photographer unknown, British Library; source page, public domain.

The Herculaneum scrolls look like lumps of charcoal. Yet Greek writing remains inside those dark cylinders. The eruption of Vesuvius in AD 79 buried the town and the Villa of the Papyri, where an exceptional ancient library was found. The heat carbonized the scrolls: that transformation helped them survive, but also made them brittle and difficult to open.

The question is one of engineering and conservation at once: how can we recover writing from an object that might be destroyed if we try to unfold it? The answer combines experimental physics, three-dimensional reconstruction, image processing, machine learning and expert reading. None of these stages is enough on its own.

Herculaneum before and after the eruption

Herculaneum was a compact coastal town about seven kilometres from Vesuvius, with decorated houses, baths and public buildings. The Archaeological Park estimates around twenty hectares and four thousand residents. The town still bore the marks of the AD 62 earthquake when Vesuvius changed its landscape for good in AD 79.

The eruption sent up ash and pumice; hours later, collapsing parts of the column drove dense clouds of hot gas and ash across Herculaneum to the shoreline. The Park gives temperatures of around 400 °C. A 2023 geological study estimated 495–555 °C for the first surge from charcoal in wood, with cooler later currents. These are reconstructions, not a single temperature measured across the town; duration, air and water mixing, and method affect the estimates. Deposits about twenty metres deep buried Herculaneum.

Remains found in the waterfront chambers, known as the fornici. Photo by Ad Meskens, Wikimedia Commons; original page, CC BY-SA 4.0. Resized and converted to WebP.

On the beach and in twelve stone chambers by the water, archaeologists found hundreds of people who had sought escape by sea. The 2001 study examined 80 of roughly 300 recovered people and proposed near-instant death from a surge around 500 °C. Later work reconstructed several surges at different temperatures. The remains document both the human toll and the eruption’s effects.

Rediscovery began underground. In 1738, Charles of Bourbon ordered shaft and tunnel excavations; work at the Villa of the Papyri began in 1750, and rolls like charcoal sticks were found in 1752. Counts vary by whether fragments are included; the Archaeological Park reports over 1,800 carbonized papyri. Greek philosophy predominates among opened works, especially texts by Epicurean Philodemus on ethics, poetry, rhetoric, music, vice and virtue. Latin works and other philosophers also appear, but the library’s full contents are unknown. UCLA’s Philodemus Project publishes editions and translations.

A book that cannot be opened

Papyrus is made of layers rolled together. Carbonization left it fragile, flattened, deformed and cracked. Pulling sheets apart can crumble them or tear away stuck layers; earlier attempts saved some text but also damaged scrolls. Some outer portions were already lost before modern study.

Instead of pulling at a sheet, researchers can pass X-rays through a scroll and reconstruct its interior. This approach requires two separate achievements: distinguishing tightly packed layers and detecting ink on a support that also contains carbon.

Light produced by electrons on a curve

The European Synchrotron Radiation Facility (ESRF) is in Grenoble, France. Early phase-contrast papyrus experiments took place there. Its BM18 beamline acquired the high-resolution scan behind the PHerc. 1667 result announced June 25, 2026, using a tuned protocol to separate layers and reveal faint signals.

Diamond Light Source in the UK contributed separate scans. Its I12 beamline examined PHerc. 172, held by Oxford’s Bodleian Libraries, in July 2024, helping recover text. A 2019 Diamond campaign scanned two scrolls and fragments from the Institut de France and recovered writing in one region.

An electric charge emits radiation when it accelerates. Changing direction counts, even at constant speed: a bicycle rounding a corner keeps its speed but changes direction. In a synchrotron, magnetic fields bend high-energy electrons circulating in a ring; undulators can make them oscillate. Their acceleration produces light, including X-rays, carried to experimental stations. Its brightness and controllability enable fine measurements difficult with conventional sources.

ESRF facility in Grenoble. Photo by Anders Sandberg, published on Wikimedia Commons; original page, CC BY 2.0 licence.

From many projections to a virtual sheet

Tomography resembles a medical CT scan: measurements from many angles are reconstructed into a 3D volume. Here, high-energy X-rays resolve micrometre details in small objects, rather than imaging a human body.

The volume shows fibres and layers, not a readable page. A papyrus surface must be located and segmented from the surrounding volume, with folds, breaks and stuck layers corrected. Geometry then virtually unfolds it into a 2D image while retaining each point’s position in the scroll.

The contrast problem

Many ancient inks and carbonized papyrus are both rich in carbon, so absorption alone may not distinguish them. Some inks contain denser elements such as lead; recipes and preservation vary. There is no universal ink or imaging trick.

X-rays also shift in phase—like a wave being advanced or delayed—as they pass through materials. After travelling some distance, these shifts can appear as intensity differences, highlighting edges, fibres or subtle deposits. This helps locate layers and may reveal strokes, but does not make every ink visible; models sometimes detect weak patterns instead.

What the model learns

Machine learning neither reconstructs tomography, flattens sheets nor translates Greek. It estimates which points on a surface contain a signal consistent with ink, learning from examples with known inputs and labels.

In the initial EduceLab-Scrolls work, researchers aligned X-ray scans with infrared photographs, where ink is easier to distinguish. Specialists marked ink or background, then projected those labels onto the volume. A supervised model learned from small 3D patches of X-ray values. One published 3D convolutional network used context across slices to produce an ink-probability map.

Ink detection in a hidden layer of fragment F4, rendered from the X-ray volume. This is not a photograph of an intact scroll or an automatic reading of words. Figure from Stephen Parsons et al., EduceLab-Scrolls, CC BY-NC-SA 4.0; converted to WebP and shared under the same licence.

Explanatory diagram, not an exact representation of a specific architecture or scan. For real examples of strokes and their labels, see the documentation of the first ink discovery and this official training animation.

For evaluation, researchers compare predictions on unseen regions against labels: which strokes were recovered, and which marks were false? Early examples were scarce and some characters went undetected. Labels also depend on alignment, preservation and human judgement, so they are not perfect ground truth.

For PHerc. 1667, a 3D convolutional U-Net-style network proposes surface locations; its geometry becomes a mesh for inspection and correction. Ink models use labels from fragments and auxiliary signals from sealed scrolls. In the PHerc. Paris 4 scan, a separate 3D network segments ink deposits directly visible in the volume. These are task-specific methods, not one model for everything.

Different papyri, scanners and inks can change the signal. Folds, breaks, damage and faint strokes challenge tracing and detection. A model therefore produces a map of probable evidence, not a transcription. Papyrologists assess letters, uncertainty, Greek meaning and context; technical teams keep each proposal traceable to the data.

What has been read, and what remains

The June 25, 2026 Vesuvius Challenge announcement presented PHerc. 1667: about 1.4 metres of surviving written surface and 22 columns or equivalents, virtually unwrapped and reviewed by papyrologists. The preliminary paper, published two days later, notes that some traces remain unreadable and lost or uncertain letters follow papyrological conventions.

The text appears to be a philosophical treatise on ethics, human nature and impulse. The name Aristocreon, linked to Stoic Chrysippus, suggests a Stoic context and probable second-century BC date; author and title remain unknown. Separately, PHerc. 139 yielded evidence for Philodemus’ On the Gods, Book 8, and Diamond’s PHerc. 172 scan revealed On Vices, Book 1.

“Reading the whole scroll” means studying all surface that survives in PHerc. 1667, not recovering missing parts or an entire original book. Layers may be broken or carry ink without enough evidence to read it; each scroll has its own geometric and imaging limits.

Ruins at Herculaneum. Photo by Christofle Van Der Meulen; original page, dedicated to the public domain under CC0 1.0.

Explore the project

Official ink-detection tutorial: code and a reproducible walkthrough of training and inference for a project ink-detection solution.
Vesuvius Challenge data and formats: scans, volumes and technical documentation published by the project.
Official ScrollPrize/villa repository: the project’s monorepo, with tools for segmentation, virtual unwrapping and ink detection. It is not a single participant’s implementation.
2026 paper on PHerc. 1667: scientific preprint describing methods, limitations, papyrological review and materials for reproducing analyses.

The work makes most sense as a chain. Physics obtains a measurement without dismantling the object; computational reconstruction locates and flattens its sheets; machine learning helps highlight ink patterns in the data; and specialists turn those signals into historical readings with explicit levels of certainty. Publishing scans, labels, code and reviews lets other teams check every stage and suggest improvements.

Computer Vision on josiete.com