• New evidence revives debate over the Book of Kells’s origins, with Scottish site Portmahomack challenging long-held Iona theory among scholars.
• A new project by master craftsman Thomas Keyes will recreate medieval vellum-making techniques to test theories about the manuscript’s production.
• The experiment may reveal how the Book of Kells was made and how long it took.

The Book of Kells is misleadingly named. It credits the Irish abbey that safeguarded the work, not the site where the mesmeric illuminated manuscript was created, which remains unknown. In fact, while it’s generally accepted that the work arrived at the Abbey of Kells at the beginning of the 9th century, its precise origin has been the subject of scholarly debate for the past two centuries.

For much of this time, the leading candidate has been St. Columba’s monastery on Iona, an island off the west coast of Scotland. The theory runs that Ionian monks fled to Kells—manuscript and relics in tow—at the end of the 8th century in response to devastating Viking raids. Iona, however, lacks the physical archaeological evidence to prove it produced a manuscript such as the Book of Kells, which used nearly 200 calfskins to depict the four Gospels of the New Testament and is estimated to have taken 75 years to complete.

In recent decades, the monastery at Portmahomack, on the northeastern coast of Scotland, has been thrust into the vacuum. Excavations carried out at the site between 1994 and 2007 uncovered evidence of a sophisticated vellum workshop, the monks’ preferred writing surface. Researchers found bone pegs for stretching hides, pumice stones for scraping hides, fire pits for producing a soda ash that dehaired hides, and even the large stone tank in which the hides were soaked. The discovery was major: Portmahomack remains the only early medieval vellum workshop to have been found in Northern Europe.

Archaeologists excavating the washing tank found at the early medieval monastery at Portmahomack. Photo: courtesy FAS Heritage.

A recently announced project could add further evidence to Portmahomack’s case. The Society of Antiquaries of Scotland has issued a grant of £2,779 ($3,700) to Thomas Keyes, a master craftsmen, to build a replica of the washing tank and produce vellum using the same methods as the Portmahomack monks of the 8th century. This will involve the aforementioned scrubbing, scraping, and stretching of hides using historically accurate tools, but one key element will be producing lye, which was used to clean and prepare the animal skins. Lime is not found locally and one theory is that monks created the alkaline solution using seaweed instead.

Master craftsman Thomas Keyes scraping animal hide over a beam in a replica early medieval vellum workshop. Photo: courtesy Norman Strachan.

The project, though potentially historically significant, is far from glamorous, Keyes said. It begins with moving rocks, digging a big hole, damming a stream, and tinkering with a culvert to make sure the right amount of water flows into the tank. Next, there’s the hides (taken from stillborn animals) and producing the lye, which offers potentially compelling proof for the Portmahomack theory of the case. The Book of Kells, which has been held by Trinity College Dublin since the 17th century, bares small pock marks from bacteria that ate into the hide while being soaked and this doesn’t happen with a lye made from lime, as was used at monasteries in Ireland, Iona, and northern England.

“The theory that the Book of Kells was made at Portmahomack is already well supported by the circumstantial evidence,” Keyes said over email. “For me, it’s now about getting into the granular detail and working out firstly specifically how each step of the process was carried out and secondly how each process could be used as evidence, either for or against the theory.”

Keyes has already tested out seaweed lye and the challenge now, he said, is seeing if he can control temperature fluctuations in the water to match the skill of Portmahomack monks 1,200 years ago. Doing so will give a sense of the scale and pace of production and hint at one of the burning questions surrounding the Book of Kells: just how long did it take to make?

The experimental archaeology may illuminate the process, but for some Medieval historians, the Portmahomack theory remains unlikely. “The existence of such a processing facility at Portmahomack will probably never be sufficient evidence,” Rachel Moss, a Medieval art specialist at Trinity College said over email. “Many such facilities existed associated with monastic scriptoria, but limited research at early monastic sites means these remain to be found.” Given the number of skins required to produce the Book of Kells, it’s possible they were brought in from a specialist production center such as Portmahomack, Moss notes, but it doesn’t necessarily provide a link.

Keyes adding colour to an illuminated manuscript design on a sheet of parchment. Photo: courtesy Norman Strachan.

The Belfast-born craftsman, who first learned letter art as a graffiti artist in the 1990s and began experimenting with vellum through processing roadkill, has considerable experience emulating Medieval manuscripts. He previously created four reimagined pages from the Book of Kells from scratch. To do so, Keyes mastered Ireland’s insular script and replicated tools found at Portmahomack including vellum, writing instruments, and inks—oak bark for black, lead oxide for red, and a specific lichen for purple.

The results will be published online by the Tarbat Discovery Centre and shared in a public lecture in late 2026. But irrespective of the findings, Keyes believes there’s wider point at play about the value of patient craft in an age where most everything is disposable.

“There’s an increasing backlash against the digital, the mass-produced and the often-shallow nature of much of contemporary art and culture,” Keyes said. “Medieval monks knew all about reality, depth, and meaning—their artwork, crafts, and processes demonstrate this and we can learn from them.”