Archaeologists have uncovered the remains of a previously "forgotten" royal castle at Finlaggan on the island of Islay, finding evidence that a substantial stone fortress stood on two small islands in a loch during the 12th and 13th centuries.
The team, which has studied Finlaggan for almost 30 years, says the structure included a rectangular stone tower similar to keeps found at Carlisle, Bamburgh and Lancaster in England, together with living quarters, courtyards, kitchens, a great hall for feasting and a chapel with an associated burial ground. The new findings are presented in a book published by the Society of Antiquaries of Scotland.
Archaeologists dated the castle to the 12th and 13th centuries, before the rise of the rulers later known as the Lords of the Isles. The Lords — whose leading families included the MacDonalds — subsequently made Finlaggan their centre of power as they controlled the Hebrides, Argyll and parts of the north‑west Highlands. The team says the earlier stone tower may have been built as a display of power and wealth, reflecting construction styles associated with contemporary Anglo‑French kings in Britain and Ireland.
Dr. David Caldwell, who led the excavation team and authored the new volume, said processing the large body of data collected since the 1990s has been a major undertaking. "The processing of all the data that was gathered has been a major part of my life since the 1990s and I hope I have not only provided an account of interest but also a basis for others to carry out more research in the future," he said.
The castle's rectangular tower resembled a keep, a heavily fortified stronghold with both defensive and domestic functions. Investigation revealed internal arrangements consistent with high-status occupation: a great hall suitable for feasting and ceremonial gatherings, separate kitchen areas, private living chambers and a chapel attached to a burial ground. The team concluded a palace was later built on the same site for the Lord of the Isles, reflecting a continuity of political importance at Finlaggan.
Researchers offered possible explanations for why the stone castle fell out of use. It may have been demolished because of structural instability or removed after sustaining damage in enemy attacks, though the team stressed such conclusions rest on the archaeological record rather than documentary evidence.
The Lords of the Isles, who later occupied Finlaggan, behaved in many respects like sovereign rulers and regarded themselves as equals of Scottish and English royalty. Historical accounts and archaeological evidence show that their activities extended beyond the islands: recorded raids by these maritime lords included attacks on mainland targets such as Urquhart Castle on Loch Ness. The discovery of the earlier castle adds a new layer to understanding how Finlaggan developed into a regional power base.
Dr. Helen Spencer, head of research at the Society of Antiquaries of Scotland, said the charity's mission was to share understanding of the past widely and that the new book is intended to make the long‑running project accessible to scholars and the public alike.
The Finlaggan project combined the work of specialists and long‑term volunteer contributors. Excavations, survey work and analysis of finds and features were carried out incrementally over decades, allowing the team to build a detailed picture of the site's changing use. The results underscore the complex sequence of occupation and construction at Finlaggan, where an early stone royal fortress gave way to later medieval palatial architecture associated with the Lords of the Isles.
The book draws together nearly 30 years of fieldwork and analysis and is intended both as a synthesis of current knowledge and as a foundation for future research. The authors say the findings illuminate the interplay of local dynastic power and wider medieval political networks in western Scotland and the islands, offering new perspectives on the material culture and built environment that underpinned lordship in the region.
Further study of Finlaggan's stratigraphy, artefacts and environmental evidence is expected to refine dating and to clarify the sequence of construction, destruction and reuse at the site. The archaeological team has made their data available to encourage continuing scholarly work and public engagement with the history of the Hebrides.
The discovery adds to a growing body of research into medieval lordship in the British Isles and highlights Finlaggan's long‑term significance as a centre of political authority in the region.