The ancient rage of Mount Vesuvius buried the town of Herculaneum, the less well-known counterpart to Pompeii, almost two millennia ago. At the time, the Roman Empire must have considered it lost for eternity, but today, scientists are working around the clock trying to excavate its secrets. Now, a new study, published in the Proceedings of the National Academy of Sciences, has revealed that lead ink may hold the key to deciphering buried scrolls uncovered from the wreckage.

Over 2,000 papyrus scrolls have been recovered to date from a single house in Herculaneum, the so-called Villa of the Papyri. Apart from carefully unfurling them to read their contents, X-rays have also been used by researchers in an attempt to glimpse what the more damaged segments of them might say.

Of the scrolls that have been able to have been read, most appear to be philosophical in nature, and written in Greek, the language of the elite in the Roman Empire. Unfortunately, it’s often difficult to tell the difference between the letters and the papyrus they’re written on, and 600 scrolls are in such poor condition that they are, at present, unreadable. The only way to potentially read these charred, delicate, unopened scrolls would be to find a way to differentiate between the ink and the paper.

Now, scientists have made a breakthrough: High levels of lead have been found within two Herculaneum papyri fragments held at the Institute of France in Paris. This could only be due to the use of lead ink, meaning that X-rays scanners could be recalibrated in order to reveal what the ink might actually say.

The research team, coordinated by Vito Mocella of the Italian National Research Council, made their discovery using the European Synchrotron in Grenoble, France, a powerful particle accelerator that can produce X-rays 100 times brighter than those used in hospitals.

^{The town was buried in ash by the eruption, and many of its buildings were incredibly well preserved such as this. pavel dudek/Shutterstock}

Significantly, this discovery pushes back the use of lead ink in Greek and Roman manuscripts by three or four centuries. “From a historical point of view, it is a surprise,” Mocella, told New Scientist.

Intriguingly, the only known use of metallic ink prior to this was specifically for the writing of secret messages around two hundred years earlier. The team are now poised, with the help of historians and translators, to reveal the lost secrets of hundreds of the most damaged scrolls retrieved from the Villa of the Papyri.

At this point, it’s anyone’s guess as to what’s written on them. On one hand, they could be extra works by Philodemus of Gadara, a prolific philosopher and protégé of Epicurus. Some historians think that the villa was used by one or both as a personal library.

Alternatively, they could be something very different: The buried library also contained a comedy, written in Latin, about a man who wants to get his girlfriend out of the hands of a pimp. Perhaps one of the charred scrolls contains a sequel.

Either way, Herculaneum’s immense scroll depository makes it one of the best-preserved libraries of the classical world. The scrolls owe their survival to the intense, rapid parching they received from the heat of the eruption in a room relatively depleted in oxygen. Instead of burning, they were carbonized into very fragile, compact blocks.