Ancient Gospel Parchment Holds a 3,500‑Year Record of the Sheeppox Virus

When scholars dust off a medieval codex, they usually expect to find beautiful script, faded inks and maybe a hidden marginal note. What they rarely anticipate is a microscopic time‑capsule of a virus that has been hunting sheep for thousands of years.

An international team led by Louis L’Hte, a PhD candidate at University College Dublin, decided to look beyond the ink. By carefully sampling the animal skins that form the very backbone of parchment – sheep, goat and even calf hides – the researchers managed to retrieve fragments of sheeppox virus DNA that had been locked away for centuries.

The study, now published in Science Advances, examined a handful of Europe’s most treasured manuscripts. Among them was the 1,000‑year‑old York Gospels, an illuminated treasure from the early Anglo‑Saxon era, and the Corpus Glossary of Corpus Christi College, Cambridge, one of the oldest English dictionaries. In several of these books, the scientists found multiple pages that still carried genetic traces of the virus, suggesting that the very animals whose skins were turned into parchment had been suffering from sheeppox at the time of their death.

“Parchment can also preserve animal pathogen DNA,” L’Hte explains. “It’s a bit like finding an old photo album that, instead of pictures, holds the molecular fingerprints of diseases that once roamed the countryside.” This revelation opens the door to a whole new kind of archival detective work – one where libraries and archives might double as repositories of ancient epidemiology.

But the surprises didn’t stop at medieval manuscripts. The team also extracted viral DNA from Bronze‑Age sheep teeth recovered from ancient pastoralist settlements across the Eurasian steppe. Those teeth pushed the virus’s timeline back even further, showing that sheeppox has been a menace to livestock for at least 3,700 years, well before the advent of modern farming.

By comparing these ancient viral genomes with those of modern capripoxviruses (the family that includes sheeppox, goatpox and lumpy skin disease), the researchers estimate that the major lineages of these viruses diverged somewhere between 11,500 and 3,700 years ago. That window neatly overlaps with the period when humans began domesticating sheep and moving them across continents, suggesting that the spread of the virus may have been tied to the very birth of animal husbandry.

One puzzling find was sheeppox DNA on parchment made from calfskin and goatskin. This could hint at rare cross‑species infections or perhaps contamination during the parchment‑making process – a reminder that ancient practices were messy affairs, just like modern labs.

Why does this matter today? Sheeppox remains a serious economic threat, with periodic outbreaks causing losses for farmers worldwide. Understanding how the virus has evolved over millennia could help scientists anticipate future changes, design better vaccines, and ultimately protect livestock populations that still feed millions of people.

In short, the pages of history are doing more than telling stories; they’re whispering the genetic history of a pathogen that has stalked sheep for generations. And as we turn each leaf, we might just learn a little more about how to keep today’s herds safe.