Local legend has long had it that the overbuilt and overgrown masonry structure known as “the Nunnery” perched over Longis beach on Alderney, a Channel Island just eight miles from the coast of France, was originally a Roman fort. Despite multiple archaeological explorations from the 19th century on, however, little evidence has been found to support the tradition. Roman stonework and tiles are visible high up on the ramparts, but they could have been repurposed during Medieval construction rather than original.
In fact, a 1930 excavation found Medieval material at deep layers and that, contrary to Roman architectural punctiliousness, the fortress was built directly on the sand. More recently, a 2002 excavation along the fallen east rampart (it collapsed from erosion sometime before the 18th century) showed Medieval midden piles at what archaeologists thought was the level of construction.
In 2008, the Alderney Society and Guernsey Museum collaborated on a project to pin down the origins of the Nunnery. With the permission of the landowner and tenants, Dr. Jason Monaghan, director of Guernsey Museums, organized a team of a dozen volunteers to spend the last week of August excavating the site. That first year they found a handful Roman objects — fragments of tile and pottery — deep down under the north wall.
Now, on the fourth consecutive year of these volunteer-staffed, week-long excavations, Monaghan and his team have found confirmation of the local legend: the remains of a Roman-era tower in the middle of the Nunnery. The team was specifically looking for one because the other 4th century Roman forts that dot northern England all have central towers, so the apparent absence of one here suggested later construction.
“The walls are 2.8m (9ft) thick, we don’t know how high it was, but it would have been a very big structure – it’s as thick as Hadrian’s Wall.”
The tower was found to be about 18 sq m. (58 sq ft). He said the team dug down to prove the outside walls were also Roman before doing the same for the gateway. [...]
Dr Monaghan said: “It’s in an extremely good state of preservation… it’s better preserved than all the other small Roman forts in Britain.
“It’s in a better state than what they call the Saxon shore forts off southern England, it’s in better nick than most of Hadrian’s Wall.
That’s one of the reasons that the legend of the Roman fort was doubted for long, because the putatively ancient part of the walls was so exceptionally high, passing 16 feet, while the remains of the forts in Yorkshire, for instance, are shin-high at best. The Roman stonework, set in characteristic herringbone patterns with double rows of tiles, was built on in later years, but you can clearly see the original crenellations that were filled in so the wall height could be raised.
The tower itself was destroyed, probably by the Nazis (I hate those guys) when they built a bunker in the middle of the ancient structure during their occupation of the Channel Islands. They were just one in a long line of people who remade the Nunnery to suit their needs over the centuries. It was a barracks in the Middle Ages, then the governor’s residence, then a farm, even British military housing after the Germans were gone.
One of the things that makes the site so interesting to archaeologists is how many periods of use are still evident. There are only a handful of Roman structures in the Channel Islands and all of them have been laid waste by time. This one shows all of its ages.