DNA can remain intact in parchment for over a thousand years. For thousands of years, humans and domesticated animals have shared a close relationship, influencing each other's lives in many ways. Animals provided food, companionship, and transportation, but they also contributed to a crucial aspect of human history: the creation of parchment. Before mass-produced paper was available, parchment made from animal skins was a widely used material for recording and preserving information. This process, which involves soaking the skins in lime water, scraping away flesh and hair, and stretching the skin to create a smooth surface, transforms biological tissue into a durable writing medium. Parchment has an additional, fascinating quality: it can preserve the DNA of the animal it was made from. Recent research shows that this DNA can survive for over a thousand years, though its preservation depends on how the parchment was stored and handled. This discovery raised intriguing questions about whether biological traces of disease could also remain in parchment. If an animal was infected with a pathogen at the time of its death, could that pathogen's genetic material survive the transformation into parchment? To explore this, researchers examined parchment samples from the University of York and the Bodleian Library in Oxford. These samples, primarily from cattle, sheep, and goats dating back to around AD700-1400, were often used in religious texts. Surprisingly, the team found strong evidence of the sheeppox virus, a close relative of the deadly smallpox virus, in many of the parchments. While sheeppox is no longer present in Europe, it remains endemic in parts of Africa and Asia. Highly infectious and lethal, especially in young sheep, the virus can leave characteristic pox scars on affected animals. The researchers found sheeppox virus DNA in 32 parchment folia, including pages from the York Gospels and the Corpus Glossary. Careful sampling using erasers helped extract minimal amounts of parchment for analysis. Traces were also found in 15th-century paper samples from France, suggesting that the virus may have been present in the region for centuries. This research has deepened our understanding of how disease impacted medieval livestock and farming. The study also included DNA analysis of animal remains, revealing that sheeppox affected European sheep herds for centuries. Even older viral genomes were found in sheep teeth from the Eurasian steppe, dating back over 3,000 years. These findings suggest that early farmers may have unintentionally created conditions that allowed pathogens to evolve and adapt to new hosts. Today, sheeppox remains a concern for farmers worldwide, with recent outbreaks in southern Europe. Understanding the biology of this virus is essential for developing better interventions and predicting how future pathogens might evolve. Further study of related viruses, such as goatpox and lumpy skin disease, may provide additional insights. The research also raises intriguing questions about the variety of infectious diseases that early societies faced, potentially altering their food security and the health of their livestock.