Thousands of years ago, Scotland’s early inhabitants were building mysterious artificial islands in lakes throughout the region—and now archaeologists have uncovered evidence that reveals these curious aquatic features to be far older than once thought.
Scattered throughout Scotland’s ancient lochs, these curious structures—known as crannogs—have long intrigued archaeologists and historians, partially due to the questions about their age.
Now, artifacts recovered from these human-built islands are pushing back the timescales on their construction, causing researchers to have to reconsider the origins of one of the most enigmatic lacustrine features in the British Isles.
The Crannog Enigma
Crannogs have been known to archaeologists for some time, with some of the earliest extensive explorations of these features undertaken beginning more than a century ago by Odo Blundell, a monk at Fort Augustus Abbey.
Constructed mostly from stone and timber, speculations about their creation extend to as early as the Bronze Age, although most scholars believe these curious features were likely to have been an invention of the Iron Age.
However, a surprising recent discovery is now challenging that presumption, revealing that some of these artificial islands date back to more than 5,000 years ago, having been built during Scotland’s Neolithic era.
Older Than Previously Thought
The story began to unfold in 2012 when local diver Chris Murray was exploring a crannog near the Isle of Lewis in Scotland’s Outer Hebrides. There, he discovered fragments of ancient pottery that experts at the National Museum of Scotland later examined, revealing an astonishing discovery: the remains of artifacts unequivocally associated with the Neolithic period.
The implication was obvious: for Neolithic pottery to have been found on this crannog would indicate it must have been constructed thousands of years earlier than the past dating of these artificial islands.
The discovery prompted a deeper look at the region’s ancient artificial islands, which soon revealed additional evidence of their Neolithic provenance. During the research, Stephanie Blankshein, a maritime archaeologist at the University of Southampton, and colleagues discovered that organic materials and artifacts from several sites across Scotland’s Outer Hebrides indicated these crannogs were likely built sometime between 4,000 and 2,500 BCE.
At least 11 crannogs in the region, Blankshein and her colleagues say, were created during the Neolithic period, pushing back the date of their construction to as far back as six thousand years ago.
Rethinking the Lives of the Ancient Scots
One of the most intriguing aspects of the team’s findings involves what it reveals about the ingenuity of the early farming communities in the British Isles, since the new dating of these prehistoric artificial islands indicates that they must have been constructed within just a few centuries of when their ancient builders arrived in the region.
Such findings align well with past genetic studies, which indicate that the region’s Neolithic populations likely descended from farmers who made their way from the Near East through Europe, and eventually settled in the British Isles, where they made their new homes by the sea.
It remains unclear, however, whether the construction of crannogs had been an innovation that occurred after they arrived in Britain, or if this had been a much earlier practice these people brought with them.
Discoveries at the Loch Bhorgastail Crannog
Among the most remarkable crannog sites is one found at Loch Bhorgastail on the Isle of Lewis. This artificial island was initially believed to have been primarily built from stone, with some evidence of timber used as reinforcement.
However, underwater excavations by Blankshein and her colleagues soon uncovered something very surprising hidden below the crannog: a massive timber platform supporting the entire structure.
“As excavation advanced, it quickly became apparent that the terrestrial and underwater components formed a single continuous structure spanning both environments and could not be treated separately,” Blankshein and her colleagues write in a recent study detailing their research at the site.
During their underwater surveys, the team discovered that the wooden foundation extended beneath the entire island and dated to between 3500 and 3300 BCE. Measuring approximately 75 feet (23 meters) across, the platform may have originally sat in shallow water or even remained dry during parts of the year.
“Loch Bhorgastail provided a rare opportunity to develop, test, and refine a workflow capable of achieving terrestrial-grade accuracy underwater,” the research team writes. “The site demonstrates the potential of shallow-water archaeology to bridge the land–water interface while elevating the precision and reliability of underwater recording.”
Lingering Questions
A fundamental question that remains about these curious Neolithic constructions has to do with what their purpose was.
One clue may arrive in the form of residues found on the recent pottery discoveries at several of these sites, which indicate they were used to transport food. This may suggest the crannogs were locations where ancient people prepared and consumed meals, possibly during ceremonial gatherings.
However, it is also possible that these ancient structures served multiple purposes, ranging from sites for communal feasting to possible locations for meetings.
Despite the lingering questions about their use by Scotland’s ancient inhabitants, Blankshein and her colleagues saw these marvelous Neolithic structures as an ideal target for high-resolution shallow-water photogrammetry, which became the focus of her team’s recent research.
“Coastal, riverine, and lacustrine environments have played a central role in the development of human societies, yet locating and documenting this record of activity in littoral environments has proven difficult,” the team writes.
As a result of their research, the team’s findings, combined with recent archaeological discoveries from over the last decade or more, help to shed new light on Britain’s ancient past, while advancing the development of new archaeological approaches. This includes groundbreaking methods for creating 3D models of shallow underwater sites, which the team achieved by using paired action cameras.
As investigations continue, Blankshein and her colleagues suspect many more Neolithic crannogs remain hidden beneath the waters of Scotland and Ireland, and with their discovery and investigation, the potential for further advancements in understanding Europe’s earliest farming societies.
The team’s recent paper, “At the Water’s Edge: Photogrammetry in Extreme Shallow-Water Environments,” appeared in Advances in Archaeological Science.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.