Fortress Britain (FB)

A new series for a new year on the concept of ‘fortress Britain’, legendary fortresses, and the  famous fortresses of Britain in the Late Antique – Early Medieval period. Fortress Britain posts will be indexed on the lost kingdoms web page in the left margin.


We must begin at the beginning with the very concept of fortress Britain. It is far older than you might imagine.

The Saxon Shore Forts

Not until the Saxon, Irish and Pictish sea raids began in about the fourth century did the Romans really concern themselves with defending Britain by sea. Of course the Roman navy based at several key ports on either end of Hadrian’s Wall at South Shields and Ravenglass, along with southern ports kept the sea fairly safe until the Roman empire itself came under threat from Germanic tribes.

There is some controversy over whether the Saxon Shore forts were to defend against the Saxons or where defended by Saxons, though the former is usually assumed. By the late fourth century a considerable number of the federate troops in Roman Britain were from Germanic tribes that may have founded the beginnings of some of the Anglo-Saxon kingdoms.

We know relatively little about what went on at the Saxon Shore forts. We know that Burgh Castle in Essex was transformed into a seventh century monastery for St. Fursey, then known as Cnobheresburg. Cnobhere is an unusual name but presumably indicates that it was the site of an English settlement.  The ruins of the fortress now served to wall off the monastery from the wider community, rather than the focus of the region. Pevensey, known to the Romans as Anderitum, is mentioned in the Anglo-Saxon Chronicle as falling to Ælle of Sussex in 491. The Chronicle claims that Ælle and his forces massacred the British defenders and surrounding territory. The map below brings home the how close the Ælle’s South Saxons really were to Kent. The taking of this Saxon Shore fort may have given the Ælle the reputation to place him on Kent’s list of Bretwaldas. Yet, Ælle apparently didn’t want the fortress and left it in ruins, perhaps as a monument to his success. The fort was left in ruins until 1042 when Harold Godwinson rebuilt the defense as his local fortress. Harold’s grandfather Wulfnoth had been a local leader in Sussex, so Harold’s interest in Sussex had a family dimension.

Map of Kent and Sussex showing Pevensey and the Isle of Thanet
Map of Kent and Sussex showing Pevensey and the Isle of Thanet

Regardless the Roman coastal defenses were the only attempt to defend the island from sea attack until the Normans. After Rome, defenses against sea-borne raiders were limited to responding to a raiding party on land. The poor Anglo-Saxon defenses against the Danes are a prime example of this.

Breaching the Sea Defenses

You may have noticed that many if not most British hillforts are located on the coast, usually on dramatic cliffs, or on river banks. All of this fortresses used the sea as part of their defense against land attack. As far as we know, none of these fortresses were bases for a sea defense. Without artillery of some kind neither the fortresses or ships of the time had the capability to attack each other in any meaningful way. Few of these fortresses actually fell to land attack; they usually passed from one ruler to the next by events away from the fortress.  The sea was the most formidable part of the fortresses defense. Before and after the Romans, the Britons and later Anglo-Saxons looked to the sea as their most important defense.

Beyond using the sea as a defense for individual fortresses, the sea was also seen as a defense for the whole island. To that end, several of the islands that lay close to Britain’s shores play a role in the legends that have evolved around the major invasions of the island. Because these islands maximized the same sea defense from the British mainland as the fortresses, they also tend to have been important British settlements and often have religious significance. Among the key islands are Thanet, Lindisfarne, Môn/Anglesey, and to a lesser extent Wight. Thanet is remembered as the first place for both the Roman and English conquest. Both Thanet and Lindisfarne are involved in legends about how the Britons nearly expelled the English from the south and north by Vortimer and Urien respectively. The legends of Vortimer and Urien are both found in the Historia Brittonum. Lindisfarne then becomes Holy Isle and  remains symbolic to this day as the first site of Viking attack. Angelsey plays  a role in Welsh lore as the site of Roman era druids and later for considerable lore that evolved around the coming of the first and second dynasty of Gwynedd.

As we shall see in the next post in this series, the English adopted the sea as their greatest defense just as deeply as the Britons.

4 thoughts on “Fortress Britain (FB)

  1. Just an interesting observation with regards to Nennius who includes three seperate `sieges`-Vortimer,Urien and Germanus

    Later the Annals cambriae describes the quite dubious notion of Cadwallon ap Cadfan being `besieged` by Edwin on Yns Seriol.
    And of course Gildas `siege `of Mons Badonicus

    Now certainly Vortimer,Cadwallon and Urien could possibly i suppose be the same event retold with different people involved?
    according to the Welsh poetry Urien isnt mentioned fighting the Angles and seems to die a natural death,can we honestly suppose he besieged the whole of the Bernician Angle race on an Island?

    Nice column,thank you

  2. The word siege is fairly common, but for a British culture whose elites usually lived in hillforts, it would be even when we aren’t talking about hillforts.

    It is unfortunate that we don’t know more about the war between Cadwallon and Edwin as the hints are really interesting. This seems to be part of a much larger story though.

    We do know how Urien died; he was assassinated by the agent of a rival Morgant often located in Gododdin/Lothian. We have to remember that these wars were fought between ruling dynasties and their supporters, so all of the Angles don’t have to be on Lindisfarne, just the warband of the ruling dynasty.

  3. A detailed entry for Aelle of Sussex can be found in the NOTHGYTH QUEST HYPOTHESIS, URL subtitled RULERS OF THE SOUTH SAXONS circa 430-825. My paper is a reconstructed history of the South Saxons and offers a list of rulers. This is a long article but ought to be studied by anyone with an interest in the early history of Sussex. By using the revelationary strength of disciplined hypothesis the Nothgyth Quest is able to throw considerable light on what has been considered an unlit corner of English history. By the way, it also discusses Natanleod and the Britons. To all those who have enjoyed reading the well-considereed article above, I extend a warm welcome to the Nothgyth Quest, David.

  4. I agree about Cadwallon and Edwin it really is an interesting area of speculation

    Was Cadwallon even King when Edwin invaded? or was Cadfan still ruling? we could even assume Cadfan may have permitted Northumbrian overlordship though his son didnt? again its only speculation

    What was Cadwallon doing on Yns Seriol to get `besieged` there? going to Church perhaps? its an awkward location to get to and certainly if it is from there he made his escape to Ireland it has to be believed with a huge degree of faith.

    How Much of Cadwallon`s recovery can we similarise with the exile of Alfred the Great? how many of the Britons actually preferred Anglo-Saxon overlordship? I would love one day for someone to write an in depth book on the subject.

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