Archaeologists unravel the history of Alderney’s Roman Fort

An excavation of Alderney’s Roman fort, also known as the Nunnery, has revealed new insights into the 1,700-year-old history of the site.

The Nunnery was only recently identified as a Roman fort, despite the site being used during the medieval period as a barracks, a governor’s house in the Tudor period, and by German forces during the occupation of Alderney in WW2.

The latest excavation works was conducted by Dig Alderney and the Guernsey Museum Archaeology Group, in conjunction with volunteers from both Alderney and Guernsey to understand the complex multi-period history of the fort.


Dr Jason Monaghan said: ‘We confirmed that the Roman tower walls had been levelled-off, probably by British engineers refurbishing the fort around 1793. The Germans inserted their Type 501 bunker neatly into the tower ruins, using the north and south internal walls effectively as shuttering to pour their concrete. Unfortunately, they dug out the entire interior of the tower to do this, destroying any evidence for internal structures or floors.”

Nunnery Dig1
Image Credit : Dig Alderney

Archaeologists were able to expose both the inner and outer faces of the south tower wall down to the top of the foundations, confirming the wall was 2.8 metres thick (around 10 Roman feet) and still standing a metre above its foundations.

After many years of study, the Roman courtyard was also exposed over a metre beneath the ground level, consisting of a double layer of flagstones embedded in clay, and in one place also capped by mortar.

Dr Monaghan inspects the intersection of the Roman tower wall with the Tudor wall, which in turn has the 1793 magazine built over it. Image Credit: David Nash

Two trenches found the remains of ‘Building D’ which could be part of the Tudor governor of Alderney’s house. It was built over the Roman courtyard and used the Roman tower for its north wall. The 1793 powder magazine was built on top of it, and again the interior of the building was largely dug out when the magazine was built leaving only a small triangle of a cobbled floor. The walls had been plastered both inside and out. More plaster was found at the base of the so-called ‘gun ramp’ suggesting that originally the lower parts of this had been the south wall of the building.


Dig Alderney had permission to excavate four areas, but planned to excavate just two of the areas during the 2021 season. The team plans to return in Spring 2022, aiming to answer outstanding questions about the medieval and Tudor history of the site.

Dig Alderney

Header Image Credit : Dig Alderney


More on this topic

Markus Milligan
Markus Milligan
Mark Milligan is an award winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 7,000 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW) and in 2023 was the recipient of the British Citizen Award for Education and the BCA Medal of Honour.




Popular stories