Those who visit the village of Dunwich today – to walk the dogs along the quiet sand dunes, or to have a pint at The Ship Inn – would be staggered to see the former city as it existed several centuries ago.

Read on to find out about its demise, and the incredibly exciting discoveries that have been made, and continue to be made, by marine archaeologists exploring the submerged settlement!

The East Anglian Capital

Dunwich was the early medieval capital of East Anglia, and the original seat of the Anglo-Saxon bishops of the 7th century Kingdom.

Once a prosperous seaport with a population of 3000, as described in the Domesday book, in the time of Henry II, Dunwich’s centre covered over a square mile. It had many chapels, churches, hospitals and splendid buildings, including a King’s Palace, as well as a harbour full of merchant shipping, and shipbuilding activities.
Over the centuries, it has shrunk considerably in size, due to storms and coastal erosion; in the Roman period the shoreline was at least 2,000 metres further out than it is today.

Nowadays, the ruins of Greyfriars’ Monastery are a striking part of the landscape, but the majority of the former city’s ruins are concealed beneath the black waves of the North Sea.

The Destruction of a City

In 1286, Dunwich was victim to a three-day storm, which wrecked much of the settlement and blocked the river mouth. Further coastal processes, including the South England flood of February 1287, St Lucia’s flood in December, and a fierce storm in 1347, silted up what had been an international port, destroying the town’s prosperity, and sweeping some 400 houses into the sea.

The Grote Mandrenke (“the drowning of men”) of January 1362 destroyed much of the remainder of the town.

The river shifted its exit 4 km north to Walberswick, at the River Blyth, robbing Dunwich of its raison d’etre. Consequently, the town was largely abandoned. Sea defences were not maintained and merciless coastal erosion progressively invaded the town.

By the mid-19th century, the population had dwindled to 237 inhabitants and Dunwich was described as a “decayed and disfranchised borough”. All Saints Church, which had been without a rector since 1755, crumbled into the sea from 1904 and 1919, and the last major portion of the tower succumbed on 12 November 1919.

Dunwich Legends

Today, Dunwich is a mere village, with a single pub and a population of around 84.

Legends have circulated over the years. One such is still well known today, especially by local fishermen:

it is said that during stormy weather, if you stand on the bleak stretch of beach where the city centre once stood, you can hear the bells of the churches ringing underwater. Sailors and fishermen will not go to sea when the bells are heard as it is a sure sign of a coming storm.

A map from 1736 had recorded churches from the old town, supposedly ‘lost to sea’ ; and  in 1973, marine archaeologist Stuart Bacon confirmed the existence of the ruins of one of those churches on the sea bed. This fed the preexisting speculation that large remains of buildings stood under the waves.

Bacon’s discovery would lead him on to an ambitious project to find the lost city of Dunwich in later years.

Finding Dunwich

In 2007, English Heritage and the Esmée Fairbairn Foundation agreed to fund a project, conceived by Professor David Sear of Southampton University and Stuart Bacon himself, to find the lost city of Dunwich.

Authoritative collations, both factual and fictional, had been written over the years regarding what existed beneath the waves, but such details were hard to confirm. Exploration through diving was extremely difficult, amongst other factors, due to there being zero visibility on the seafloor and strong tidal currents. Thus, the team proposed to map out the entire area using geo-acoustic survey techniques.

The Dunwich 2008 Project

The Dunwich 2008 Project aimed to first collate all existing mapped data in order to create one accurate projection and coordinate system; old maps, if correct, could give them a good idea of the likely boundary of the former city. They could then use this map to inform their underwater survey.

They would conduct a detailed “bathymetric” and “sub-bottom” profiling of the sea and city, and deliver the information to the public via the town’s museum.


The geophysical underwater survey used a suite of integrated computerised electronic systems, mounted on a shallow draught vessel, to gather its results.

It used GPS to position the vessel relative to those coordinates obtained from the mapping stage, and an internal, electronic gyroscope to compensate for movement on the vessel.

Side scan sonar, a specialised sonar (Sound Navigation And Ranging) system used for  searching and detecting objects on the seafloor, would be used to see what the divers could not.

Side scan sonar technology transmits sound energy and analyses the return signal (or echo) that bounces off objects.

The energy is formed into the shape of a fan that sweeps the sea floor from directly under the towfish  (see the diagram) for a distance of up to 75m.

Measuring the strength of the return echo continuously allowed them to create a picture of the ocean bottom, and any ruins protruding from it.

The team also used a piece of apparatus called an Applied Acoustics ‘Boomer’ catamaran. It emitted a high frequency, low energy pulse which could penetrate beneath the seabed and detect significant buried objects.

Though conditions were near impossible to work in, diver surveys were also used to “ground truth” the targets seen on the geophysical survey.

Four dives were made on two separate targets, when the water was slack between high and low tides. Divers were clipped to a guide rope, which was fixed to a heavy weight dropped on the target, and descended into the black depths of the North Sea.
Photography was not revealing, but the divers mapped structures and materials they felt on the seafloor.

They reported feeling, for instance, stone walls and smooth worked stone at both targets. At the northern target – the site of St Peters Church – one diver reported entering a “room-like” arrangement of flint and mortar walls.


St Nicholas Church & St Peter’s Church

St Nicholas Church was the wealthiest in Dunwich. It collapsed over the cliffs in the late 15th century (c1480AD).
Its ruins appeared as scattered blocks of masonry on the multibeam image, and divers confirmed the presence of fragments of wall. Two stones were recovered from the dive, which still had medieval mortar attached. This confirmed their origin as part of a manmade structure.

The site of the church lies some 410m east from the 2000AD cliff line, at a depth of 8.4m.

Slightly closer to the present day coast, at 337m and at a depth of 10m, is the site of St Peter’s Church. The church had collapsed over the cliffs during a storm of c.1688-1702.  This was the site discovered by Bacon in 1973. Blocks of masonry walls were detected, measuring up to 5m in length and standing up to 0.6m proud of the sea floor. Side scan sonar images also showed linear features and blocks of masonry on the site. The sea floor was covered in large flints and stones that had fallen out of walls, as lime mortar dissolves over time.

The location of the Knight’s Templar church and All Saints’ church are known from the digital mapping but remain buried beneath an inner sandbank. The early town is buried under 1-3m of sand to the east of the ruins found by Bacon and these later surveys.

Further Explorations

A large survey and update to the mapped data was commissioned by English Heritage in 2011 and reported in 2012. The results have produced the most comprehensive survey of the Dunwich town site – the largest medieval underwater site in Europe. Data from these surveys and explanations of the technologies used to make the findings are now displayed in Dunwich Museum. You can read the full report of the 2012 survey here.

Further work to explore new sites using similar sorts of surveys, and a campaign of land-based archaeology, began in 2013, funded by the “Touching the Tide” Heritage Lottery Fund Landscape Partnership Scheme.  A new shipwreck has been found off the coast during these investigations.

Professor Sears, who leads the new diving team, explains:

“We have located a new wreck, which itself reminds us of the dangers of this coast, and the variety of the heritage that can be found in the coastal zone… For Dunwich, we’ve added another archaeological site to the inventory of sites that make this among the most extensive and unique marine heritage areas in the world.”

Visit Dunwich Museum to find out more about the history of Dunwich. The coastal town of Orford is also home to the Suffolk Underwater Studies Museum, which may be of interest to those looking to find out more about marine archaeology along Suffolk’s coastline!

And if you’re keen to stay in the area and explore the beautiful Suffolk Coast and its fascinating heritage, take a look at Bridge Cottage, Dunwich, just a couple of minutes walk from the beach!