Recreating early medieval manuscripts: Tarbat Discovery Centre, Portmahomack

This article is from Current Archaeology issue 435

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The elaborately decorated Book of Kells takes its name from the eponymous abbey in Co. Meath where it was kept for centuries, but it has been previously suggested that the early medieval manuscript was created on Iona. Now, thanks to a grant from the Society of Antiquaries of Scotland, a new experimental archaeology initiative is exploring whether it could indeed have been produced in the Scottish Highlands.

During this project, Master Craftsman Thomas Keyes aims to recreate the process of early medieval vellum production, drawing on archaeological evidence from Portmahomack, a Pictish monastery that flourished from c.AD 680 to 820. Excavations on the site, led by Professor Martin Carver FSAScot and Cecily Shakespeare FSAScot in the late 1990s and early 2000s, revealed the remains of a vellum workshop (see CA 205 and 321). Key findings included bone pegs that would have been used for stretching the vellum as it dried, along with knives and pumice stones for scraping and smoothing the hides. As the only known parchment-production site of this period in northern Europe, Portmahomack is considered to be a candidate for the source of the Book of Kells – and Thomas Keyes hopes to learn more about how it was created.

Another important discovery at Portmahomack was a 1,500-litre stone lined tank, which was found alongside a number of hearths, all of which produced evidence of burning toothed wrack seaweed. It is thought that this seaweed would have been used to form soda ash, an alkaline substance serving the same purpose as lime, which is not local to the area – it would have been mixed with water and added to the tank along with animal hides to dehair them. As seaweed lye is less caustic than lime, it may have allowed bacteria to develop – something that might explain the numerous pockmarks seen on some of the pages of the Book of Kells. Thomas Keyes has already successfully recreated parchment using medieval techniques and replicas of tools from Portmahomack; now, thanks to the recent funding, he will be able to recreate the washing tank in order to produce new parchment using seaweed lye, and then compare the results with pages from the Book of Kells.

Text: Kathryn Krakowka / Image: Norman Strachan