ABERDEEN, Scotland, July 28 (UPI) -- A rock outcropping along Scotland's northeast coast has been confirmed as the earliest Pictish fort, a seaside stronghold of the tribal people that briefly ruled the northern British Isles during the Late Iron Age and Early Medieval periods.
The outcropping, known as Dunnicaer, has long been a fixture of the Aberdeenshire coast, but hasn't been extensively studied until now. The weathered foundation of the sea stack is surrounded by steep cliff on all sides, making it a difficult place to execute an archaeological dig.
But a team of archaeologists from the University of Aberdeen, aided by the expertise of experienced mountaineers, were finally able to uncover the secrets of Dunnicaer. Beneath the surface, researchers found evidence of ramparts, floors and a hearth.
Carbon dating puts the fort's foundation sometime in the 3rd or 4th century, making it the oldest Pictish fort yet discovered.
"This is the most extreme archaeology I've ever done," lead archaeologist Gordon Noble said in a press release. "The site can only be accessed using ropes at low tide and having never climbed before, it was quite hair-raising."
But Noble and his colleagues say the anxieties of cliffside digging quickly faded as their work revealed remarkable findings.
"Dunnicaer appears to have been home to a significant fort, even at this early date," Noble explained. "We can see there were ramparts, particularly on the south side, constructed of timber and stone. This is consistent with the style of later Pictish forts."
Researchers point to the impressive size of the stone and timbers used in constructing the fort, materials that had to be brought in from elsewhere -- quite a feat, they say, for the time period.
"It is likely that the sea stack was greater in size than it is today as the fort appears to extend over a large area," Noble said. "Dunnicaer was likely to have been a high status site for a structure of this scale and complexity to have been present as early as the 3rd century."
Bigger or not, researchers say it's clear the fort quickly became too cramped for the local Pict tribes, as dating suggests the sea stack was not long occupied.
"It is likely that it became too small and the communities who built it moved along the coast to what is now Dunnottar Castle."
Researchers also point out the fort was likely actively eroding, even in its earliest days. The scientists hope their discovery can help solve the mystery of where the Picts originated from and what precipitated their disappearance toward the end of the 3rd century.