When the En-Gedi scrolls were excavated from an ancient synagogue's Holy Ark in the 1970s, it was a bittersweet discovery for archaeologists. Though the texts provided further evidence for an ancient Jewish community in this oasis near the Dead Sea, the scrolls had been reduced to charred lumps by fire. Even the act of moving them to a research facility caused more damage. But decades later, archaeologists have read parts of one scroll for the first time. A team of scientists in Israel and the US used a sophisticated medical scanning technique, coupled with algorithmic analysis, to "unwrap" a parchment that's more than 1,700 years old.

Found in roughly the same area as the Dead Sea Scrolls, the En-Gedi scrolls were used by a Jewish community in the region between the 8th century BCE and 6th century CE. In the year 600 CE, the community and its temple were destroyed by fire. Archaeologists disagree on the exact historical provenance of the En-Gedi scrolls—carbon dating suggests fourth century, but stratigraphic evidence points to a date closer to the second. Either way, these scrolls could provide a kind of missing link between the biblical texts of the Dead Sea Scrolls and the traditional biblical text of the Tanakh found in the Masoretic Text from roughly the 9th century. As the researchers put it in a paper published in Science Advances:

Dating the En-Gedi scroll to the third or fourth century CE falls near the end of the period of the biblical Dead Sea Scrolls (third century BCE to second century CE) and several centuries before the medieval biblical fragments found in the Cairo Genizah, which date from the ninth century CE onward. Hence, the En-Gedi scroll provides an important extension to the evidence of the Dead Sea Scrolls and offers a glimpse into the earliest stages of almost 800 years of near silence in the history of the biblical text.

How to read a burned scroll with computers

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But it wasn't until University of Kentucky computer scientist Brent Seales developed a technique he calls volume cartography that archaeologists actually got that "glimpse." Seales had previously worked on a project to read fire-damaged scrolls from the library of a wealthy Roman whose home in Herculaneum was buried in hot ash during the eruption of Mt. Vesuvius that also destroyed Pompeii. He suggested that Israel Antiquities Authority archaeologist Pnina Shor scan the scrolls using X-ray micro-CT, which is essentially a very high-resolution CT scan of exactly the same type you might get in a hospital. Indeed, Shor explained in a press conference that her team used a medical imaging facility to produce digital scans that she sent to Seales to analyze in Kentucky.

Seales used a three-step process of "segmentation, texturing, and flattening" to recreate the writing on the surface of one of the scrolls. In segmentation, researchers break the 3D scan down into very small pieces, searching for the surfaces of each page. Because the scroll wasn't just rolled—but actually crushed and burned—each page surface has an arbitrary shape. But eventually, Seales and his team mapped a triangulated surface mesh to each surface and had a pretty good map of where in the scroll they might find ink.

During the texturing and flattening phase, Seales writes that "each point on the surface of the mesh is given an intensity value based on its location in the 3D volume." The higher the intensity, the more likely it is to be writing. One scroll turned out to have metal-based ink, which made the process slightly easier. Finally, during the flattening stage, the team "maps the geometric model (and associated intensities from the texturing step) to a plane, which is then directly viewable as a 2D image." In other words, the scroll is virtually unwrapped, with the letters appearing to glow on its surface. Of course, the scroll was severely damaged by fire, so there are big pieces missing.

During a press conference, Seales explained the above image:

If you look at the top edge, the cutout pattern of the master view image... there are sections that are missing... Imagine that the scroll is being rolled from the left to the right across that figure two. On the left are the outermost layers, and on the right are the innermost layers. The notches along the top edge, and the larger cutouts actually on the bottom edge as well, those are places where the layer being unwrapped comes back around—a re-revolution to a damaged section. After about five complete revolutions, you get to the right-hand side of the master view and you can see the center of the scroll. And in those innermost layers, on the center part of the scroll, you can see scoring marks that look like cracks, but they’re all lined up. That’s where the scribe probably made lines to follow in writing the text.

Seales noted that his volume cartography technique will be released as open source software next year.

Historical significance

Once Seales and his team had this visualization, they still weren't sure what they had. None of them read Hebrew, so they waited with some excitement while Shor and her colleagues analyzed the text. It turned out that the scroll contained the first two chapters of Leviticus, which coincidentally deal with burnt offerings. What's incredible about these chapters, according to archaeologist Emanuel Tov, is that they are virtually identical to medieval Masoretic Text, written hundreds of years later. The En-Gedi scroll even duplicates the exact paragraph breaks seen later in the medieval Hebrew. The only difference between the two is that ancient Hebrew had no vowels, so these were added in the Middle Ages.

Tov called it "100 percent identical with the medieval texts, both in its consonants and in its paragraph divisions." He added, "The same central stream of Judaism that used this Levitical scroll in one of the early centuries of our era was to continue using it until the late Middle Ages when printing was invented... the scroll brings the good news that the ancient source of the medieval text did not change for 2,000 years." In other words, the Jewish community managed to retain some of the exact wording in passages from their biblical texts over centuries, despite massive cultural upheavals and changes to their languages.

Archaeologist Michael Segal said the En-Gedi scroll "teaches us that the [biblical] text that we have that is used today as the traditional text is a very ancient text in all of its details." He cautioned that of course only the consonants are the same, and we have yet to read the rest of the En-Gedi scrolls. Still, this scroll provides strong evidence that today's Tanakh "already existed in a standardized form in the first century C.E."

A boon to intelligence agents?

The archaeologists involved in this project are eager to use Seales' software to unwrap other damaged scrolls, particularly some of the Dead Sea Scrolls. And Seales wants to do more with the Herculaneum collection to learn more about the reading habits of ancient Romans.

However, there are many other uses for volume cartography. Seales admitted that there had been interest from the intelligence community. "I'm sure that security and intelligence constantly is looking for ways to extract better information noninvasively from materials," he said. "So that’s what we’re doing, and we’re doing it at a very high resolution, so anything that requires the resolution that goes down to microns in the intelligence world will probably be interested in this technique."

So if you're considering a career in spycraft, just remember that burning the evidence may not be enough anymore. The same technique that allows scientists to read ancient burned scrolls will allow intelligence agents to read your charred secret messages, possibly years or decades later.



Science Advances, 2016. DOI: 10.1126/sciadv.1601247

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