From Atlas Obscura:

Found: A Medical Manual Linking Medieval Ireland to the Islamic World

Knowledge transcends borders.

AN EXCITING LINK BETWEEN MEDIEVAL Ireland and the Islamic world has been discovered on two sheets of calfskin vellum lodged into the binding of a book from the 1500s. The sheets hold a rare 15th-century Irish translation of an 11th-century Persian medical encyclopedia. For 500 years, they sat in a family home in Cornwall with no one the wiser to their origins.

“I suppose [the owners] just took a notion to photograph it with their phone and they sent the photograph to one of the universities in England, who sent it to another university, and eventually it got to me,” says Pádraig Ó Macháin, who has spent his life with medieval Gaelic manuscripts and leads the modern Irish department at University College Cork. For him, identifying it as a medieval Irish medical text was a cinch, but he needed a little help to determine its source.

Ó Macháin, founder of Irish Script on Screen, Ireland’s first deep digitization project, where the manuscript and many more old Irish texts can be seen, shared the fragment with Aoibheann Nic Dhonnchadha, a specialist in Irish medical texts at the Dublin Institute for Advanced Studies. She identified it as a passage from the first book of the seminal five-volume The Canon of Medicine.Written by 11th-century Persian physician and polymath Ibn Sina, also known as Avicenna, the work is considered the foundational textbook of early modern medicine. While many references to Ibn Sina and his work pop up in old Irish medical texts, this is the only known evidence of a full translation of his encyclopedia. He originally wrote in Arabic, and the Irish rendition is likely translated from a 13th-century Latin version by the prolific Gerard of Cremona. “This is one of the most influential medical books ever written,” says Nic Dhonnchadha. “So the fact that it was being studied in Ireland in the 15th century was certainly a link to the Islamic world.”

More at the link.