In the 11th century, the Persian physician Ibn Sīnā wrote a five-volume medical encyclopedia called the Canon of Medicine, which, among other things, covered the basic principles of medicine as they stood at the time and listed around 800 drugs that could be used for treatment. The influence of this expansive work spread beyond the Middle East to Europe, connecting the Islamic world to such far-flung locations as Ireland, as a new discovery shows.

According to Atlas Obscura’s Noor Al-Samarrai, two sheets of a 15th-century translation of the Canon of Medicine were recently found inside the binding of a 16th-century book. More specifically, reports the Guardian’s Alison Flood, the manuscript had been trimmed and sewn into the spine of a Latin manual dealing with local administration, which has been owned by the same family in Cornwall, England, for the last 500 years until the modern-day owners noticed the strange text stitched into the binding.

In search of answers, they consulted Pádraig Ó Macháin, a professor of modern Irish at the University of Cork, who realized he was looking at a medieval Irish medical manuscript. Aoibheann Nic Dhonnchadha, an expert in Irish medical texts at the Dublin Institute for Advanced Studies, helped identify the fragments as a translation of the Canon of Medicine.

“It really was very, very exciting,” Macháin tells Flood, “one of those moments which makes life worthwhile.”

The find was so thrilling in part because of its rarity. References to Ibn Sīnā’s encyclopedia appear in Irish medical texts from the medieval period, but the newly discovered fragments are the first to show Canon of Medicine was translated into Irish. The fragment that was stuffed into the 16th-century book binding covers the physiology of the back, jaw and nose. The translation was likely based on a Latin translation of the Arabic original.

Ibn Sīnā, also known as Avicenna, was a prolific polymath whose writings covered not only medicine, but also theology, astronomy, philosophy, physics and mathematics. But it was largely the Canon of Medicine that made him an esteemed figure in Europe; the book was a core part of the European medical curriculum until the 17th century. Throughout this time, Ireland was “very much pre-urban,” says Ó Macháin, the professor of modern Irish. That being said, the fact that Ibn Sīnā’s seminal medical text was translated into Irish shows that the country was also a center of scientific study.

“[T]here were great schools of learning here, including medical schools,” he tells Al-Samarrai. Irish would have been the language of study, rather than Latin.

In the early centuries of printing history, it was not unusual for manuscript fragments to be used in the binding of other books; parchment was expensive, and it made sense to use recycled material instead of fresh sheets. But that the translation of the Canon of Medicine would have been valuable, and its owners may not have willingly pulled the book apart, suggests Nic Dhonnchadha of Dublin Institute for Advanced Studies. When the English Tudors expanded into Ireland in the 16th century, many Irish texts were destroyed or cut up. Perhaps the translated Canon of Medicine was one of them, she tells Al-Samarrai.

Somehow, a fragment of the book survived to the present day. That text can now be seen on Irish Script on Screen, which was founded nearly two decades ago by Ó Macháin with the goal of creating digital images of other precious Irish manuscri