Riduna: Alderney in the Roman Empire
Jason Monaghan
Alderney was part of the Roman Empire for over 400 years. It was one of the islands called the Insulae Lenuri
and was known as Riduna. Not much was known about Romans in the Channel Islands until the 1980’s when
Roman buildings were found in St Peter Port and a shipwreck was raised from its harbour. At least four more
Roman shipwrecks are now suspected around Guernsey. Jersey also had the remains of a small temple
The Romans commanded by Julius Caesar conquered the nearby coasts of Gaul in 56BC. Guernsey may
already have been friendly to the Romans before this as ships had been stopping there carrying Roman pottery
and wine possibly as early as 120 BC. Guernsey was on the route taken by merchant ships sailing up the
Atlantic Coast of Gaul and into the Channel. Most would have avoided Jersey as it did not have a good harbour
and was ‘in the corner’ surrounded by dangerous reefs. Alderney’s rocks and currents were also to be avoided.
Ancient sailors however liked to sail in sight of land so it is likely they would have used Alderney as a navigation
point when sailing north from Guernsey, or south out of the Channel.
Roman objects found in the islands came from modern France, Germany, Britain, Spain, Italy, North Africa and
Palestine. Trade goods included olive oil and fish sauce carried in amphorae (large jars). Each style of amphora
came from a different region and experts have worked out what many of them carried.
Remains of Roman buildings have been found two metres under the sand at Longis Common. Longis was a
natural harbour and seems to have been the main settlement in Roman times. It is possible that a whole village
is buried under the sand at Longis. Roman graves called ‘cists’ were found eroding out of the sand-dunes on the
top of the beach before the Germans built their sea
wall. Roman roof tile is also found on the beach. It is
possible that the Channel Islands were governed
from the Roman town of Constantia (modern
Coutances).
A Roman small fort was built at the Nunnery to
guard the harbour at Longis. The fort was probably
built in the middle of the fourth century, but there
may have been an earlier building on the same site.
It is the best surviving small fort in Britain, with the
walls still standing up to 5m high. It is approximately
40 metres square with walls up to 2m thick. It has rounded corners with semi-circular bastions that may have
been designed to carry bolt-shooting catapults (ballistae). Originally it had a massive square tower in the centre,
with walls 2.8 metres thick.
The Nunnery was probably a base for the Roman navy, which would have mounted patrols against pirates and
raiders to stop them sailing through the Race. It was built at a dangerous time for Rome when ‘barbarian’ tribes
were attacking from the direction of Germany and the North Sea. The Romans used small fast warships called
‘picti’ which were painted blue to hide them while hunting pirates. The Nunnery also stopped the pirates
themselves using Alderney as their base. The Nunnery would have come under the command of a Roman
general known as the Duke of Armorica (dux tractus Armoricani et Nervicani).
In AD 410 the Romans abandoned Britain and in AD 486 the Franks defeated the Roman armies and took
control of Gaul. We do not know exactly when, but at some time between AD 400 and AD 500, Alderney ceased
to be controlled by Rome.