Unique among the territories of the Western Roman Empire in the 5th century, Britain succeeded in holding back and even reversing the tide of Germanic conquest for nearly two centuries. This was an age of heroes… It was the Age of Arthur!

This is the twelfth-part of our discussion of Britain in the so-called Age of Arthur: the 5th though the mid-6th Century A.D. It is a fascinating period, with the Classical civilization of Greece and Rome giving way to the Germanic “Dark Ages”. It was the sunset of Celtic-Roman culture in Britain; it was the Age of Arthur!

But who was Arthur?

Before we answer that question, it is necessary we understand the world in which he lived.

(Read Part Eleven here. Or start from the beginning, with Part One!)


The earliest author from which we have any details on Arthur’s military career is Nennius; a 9th century Welsh monk. He states that Arthur fought twelve battles against his enemies before the climatic engagement at Mount Badon (Mons Badonicus). It is important to keep in mind that Nennius wrote three centuries after the events he purports to chronicle. He may have had available to him sources lost to us today; so shouldn’t be dismissed out of hand. Nor should we accept his account without skepticism. That said, as it is our purpose here to build a “working theory” on who Arthur may have been, and using what sources and artifacts that are left us we can take Nennius as a road map, however sketchy. We can attempt to place the location of his twelve battles, and so trace Arthur’s career and rise to supreme power amongst the Celtic kings of Britain.

We have already discussed the first of these twelve battles, the battle at the River Glein, in our last installment. The year is 507[1], and Arthur the Dux Bellorum (war leader) of Britain and his band of mounted Combrogi (“fellow-countrymen”, comrades-in-arms) range across Britain, responding to foreign threats and incursions. In this year they have come to Lindsey and defeated a band of Angle pirates at the mouth of the Glein. This was the first of Nennius’ twelve battles.

In his Historia Brittonum, Nennius writes that Arthur’s “second, third, fourth, and fifth battles were above another river which is called Dubglas and is in the region of Linnuis...”

1463965Roman Lindum (Lincoln), viewed from the southside of the Witham (Dubglas?) River

Linnius is most likely Lindsey, the area around Lincoln (then Roman Lindum). On the fringe of the Anglo-Saxon zone of occupation, this Roman city was largely deserted by the first decade of the Sixth Century. It may have still contained a Romano-British garrison, or even been the seat of an independent British chieftain. In the last installment we discussed the possibility that Lindum was an outpost of the British kingdom centered on York (Eburacum). This may have been the North Yorkshire kingdom of Elmet, or a minor petty-kingdom (or city-state) which scholars sometimes refer to as Ebrauc (or Cair Ebrauc). Alternately, it may have been incorporated into an early Anglo-Saxon petty kingdom in Lindsey.

But then what modern river can we identify as the “Dubglas” (which translates as “Black Water”) River, where Arthur’s battles were fought? Lincolnshire has many small muddy rivers, flowing off the peet moors of the Midlands into the Wash or directly into the North Sea. Some have identified the Trent as the possible candidate; and Arthur’s presence here might have been in response to an Angle incursion deep into the region, which threatened to cut the main road between the northern and southern British kingdoms.

In my opinion, though, the most likely candidate is another of the great rivers of Britain: the Witham. This flows in a great curve through Lindsey, past Lindum and then bending southeast, flowing eventually into The Wash. Its dark flow could easily be described as the “black water”.

1463972.jpgThe Withan River: could this be the Black Water?

It is no coincidence that many of Arthur’s battles take place at rivers. Rivers are naturally defensible obstacles, often forming the borders between peoples. Many of the battles between the Britons and the Anglo-Saxons over the next century were fought at the fords of such boundary-rivers. The Angle settlements in Lindsey were likely near the coast, and the Witham/Dubglas may have separated them from a British outpost at Lindum. Another possible scenario is that the Angles of Lindsey decided to eliminate this British outpost, and Arthur came to break this siege.

Another question arises: Arthur fights his next four battles along the “Dubglas”. Why so many? It must be remembered that Nennius gives no time-frame for these next four battles. Were they fought in rapid succession; or over a period of years?

While we can never know for certain that the puzzle pieces, however well fitted, are correct a working hypothesis presents itself:

Once the thriving capital of the Roman province of Flavia Caesariensis, by the dawn of the 6th century Lindum had long been on the frontier-zone, and may have been deserted by its civilian populace. But its location was strategic, as two major Roman roads met here: Ermine Street, the main north-south artery in the east, connecting Londinium to Eburacum (York) and beyond to the foot of the Highlands; and the Fosse Way, the main cross-island highway connects Lindum and the Kingdom of Elmet with Arthur’s own home kingdom of Dumnonia[2].

It is very likely that the ruler of Elmet (who Castleden identifies as Gurgust Lethum, descendent of Cole Hen, born 490 AD; though others identify this monarch as already reigning in the 490s) maintained a beleaguered garrison here.

1463975Roman Britain, at the end of the Roman occupation. Though the adminstrative divisions of the island imposed by the Romans had disappeared by the 6th century, replaced by Sub-Roman Celtic successor kingdoms; the Roman road network was still in existence and vital to trade and the military unit of the British kingdoms.

It was perhaps the siege of this garrison, and the awareness of the threat an Angle-held Lindum would present to the integrity of Celtic Britain, that precipitated Arthur’s campaign against the Angles in Lindsey. Or this operation could have been a coordinated effort between Arthur and the forces of Gurgust to destroy Anglish Lindsay. In either case, Arthur was on his way to Lindum, moving north up the Fosse Way when he learns from local peasants about an Angle warband landing at the nearby mouth of the Glein . This first of Nennius’ twelve battles was but an unplanned meeting engagement; wiping out this chance incursion. (See Part Eleven)

These destroyed, Arthur now rides swiftly northward. It is only 40 some miles to Lindum from the Glein/Glen near modern Spalding. The following day Arthur suddenly appears unexpectedly in the rear of the Angle host besieging the fortress.

Surprise is the greatest of all assets in war. As the German Panzers showed during the blitzkrieg, and the Mongols demonstrated 700 years before them, rapidly moving mobile forces can outstrip news of their coming to achieve decisive strategic and even tactical surprise. In this fashion, Arthur and a small force of hard-hitting heavy cavalry could seem to appear out of nowhere, strike a blow, and then fade away; leaving terror and death in their wake.

1463993.jpg Late Roman reenactors: Arthur’s Combrogi might have looked very much like this!

Close beneath the southern walls of Lindum the Dubglas/Witham flows west to east before turning southeast toward the Wash. Perhaps in the meadows on the south bank of the river the British fought the second of Nennius’ battles, and the first in the series along the “Dubglas”. The outcome of the battle may have been a British defeat; or, if a victory, certainly not a decisive one. In either case, three more would be waged here.

Let us assume Arthur was victorious in driving the Angles from around Lindum. After feasting with his ally King Gurgust within the fortress walls, Arthur leads the combined forces deeper into Anglish Lindsey. Let us imagine that the Angle host has crossed the Dubglas/Witham down-river, camping now on the east bank, defending a ford. Here is fought the third of Nennius’ battles. The Britons arrive, and attempt to force the crossing. The Angles, holding the opposite bank, resist with their customary ferocity.

1463977.jpg A ford of the Witham River

This is an infantry fight: the ford restricts the frontage, and even the best cavalry cannot force their way frontally through a determined shieldwall. Besides, Lindey is wet, marshy land, far from ideal for cavalry operations. Arthur and his armored Combrogi dismount and join Gurgust’s household troops in the battle in the ford.

Though Nennius indicates that, as in all of these, Arthur was victorious, it is more likely the battle resulted in a stalemate, if not a downright British repulse.

Both sides withdraw to lick their wounds. It is late in the season. The belligerents return to their homes for the winter.


Britain did not exist in a vacuum, and events in Britain likely reverberated across the Channel. Arthur’s “word fame” had spread beyond Britain’s shores.

Warriors seek three things in life: A cause to fight for; comrades to fight beside; and an inspiring leader to follow. We can only imagine that individual warriors, “free lances” in search of employment, flocked to Arthur’s standard; swelling the ranks of the Combrogi of his Comitatus.

In 507, the fame of the “Dragon Lord” attracted a more substantial reinforcement.

That year, a decisive battle was fought in Gaul. Clovis, first King of the Merovingian dynasty of the Franks, defeated the Visigoths at Battle of Vouillé/Campus Vogladensis. The result was the end of Visigoth rule in Gaul, as the descendants of Alaric and Euric retreated back into their territories in Spain. Gaul was on its way to becoming France.


John Morris suggests that as a result a Visigoth noble named Theodoric, commanding the Visigoth naval squadron in the Bay of Biscay, arrived in Cornwall seeking sanctuary for himself and his forces [3]. The evidence supporting this theory is questionable, and much of Morris’ theory that follows is highly speculative. But it is an interesting one to contemplate.

We know a Theodoric ruled in Western Cornwall from about this time, into the middle of the century. During which time he repelled Irish incursions and settlements in Cornwall and south Wales. The theory that Theodoric was a Visigoth expatriate is mostly based upon his name; which is indeed Visigoth, and one not yet in usage by the Britons or Franks.

With the Franks driving the Visigoths from Gaul, could this Theodoric have brought a Visigoth fleet and band of warriors to join the Pendragon of Britain?

Cornwall (Kernow) was ruled by several petty king, all possibly vassals of the King of Dumnonia. It is highly unlikely that such a Visigoth settlement in Cornwall would have been tolerated had not the newcomers been accepted by the local authorities, and by Arthur; who while not yet accepted as High King of Britain, filled the role of Dux Bellorum, the de facto warlord of Britain.

If we allow that Theodoric may have been a Visigoth émigré, and that he was welcomed by Arthur and the Dumnonii, then we are left with the picture of a powerful naval lieutenant based near Lands End, at the tip of Cornwall. He is charged by Arthur with patrolling the southwestern coast; both warding against and eradicating Irish/Scotti settlements. This is the role Theodoric played faithfully for the next several decades. His loyalty and competency secured Britain and Arthur’s southwestern flank, allowing Arthur to concentrate on defeating his Anglo-Saxon enemies and recovering the “Lost Lands” of Lloegyr.


Continuing with our hypothetical scenario, the following spring Arthur returns to Lindsey to continue the war against the Angles under their chieftain, whom (following Geoffrey of Monmouth, for want of a better source) we will call Colgren. This time Arthur brings a force of infantry to augment the Elmet levy, perhaps even some of Theodoric’s Visigoth warriors. King Gurgust is waiting at Lindum with the forces  of his kingdom, stiffened by his own “Teulu” (household troops). The combined forces were likely not more than 2,000 and very likely under 1,000. Of these, the professional warriors of Arthur’s Combrogi numbered no more than 500, and likely closer to 300; Gurgust’s Teulu likely another 120 men. If Theodosius’ came with some of his Visigoths, perhaps these numbered as many as 300 more (more would have been a threat to the British themselves).

All or most of these professionals would have been cavalry. The rest, the militia of Elmet (perhaps including some of the town militia of Eburacum/York and Lindum/Lincoln), would have been infantry levies armed with spear and a small number of archers.

Once again the armies engage at the River Dubglas, in the fourth of Nennius’ Twelve Battles. We don’t know the outcome (Nennius states that Arthur was triumphant in this battle, but if so it was an indecisive victories). But a plausible scenario is this:

Colgren’s host, perhaps augmented by additional bands of Angles and Saxons as winter gave way to spring, would have mustered behind the Dubglas/Witham; perhaps near Bardney, a plausible location. They were prepared to oppose the Britons at the fords. With his cavalry advantage, Arthur would have had little trouble locating the enemy; the Anglo-Saxons, an infantry host, less so. On the day of battle, Arthur drew up the British infantry (likely led by Gurgust) at a ford opposite the Angles. Pushing across, the Britons engage the Anglish shieldwall in close combat.


Meanwhile, Arthur leads a flying column of cavalry and his lightest infantry across the river at a higher crossing place. Lindum is on the left-bank: perhaps Arthur set out before the rest of the host, taking the circuitous route along the marshy and heavily wooded left-bank. At the height of the fighting, he appears behind and on the right flank of the fully-engaged Anglish!

The Angles are brave warriors, and fight stubbornly. But their flank crumbles under the sudden assault. It is unlikely that the surprise was complete, and Colgren is able to withdraw the bulk of his forces to fight another day. Perhaps his doomed right flank buys the rest time to get away.

But the Britons are across the river, and now advance down the left (eastern) bank of the river. We don’t know where the main stronghold of this early Angle settlement was. But if it was near the mouth of the Witham (a logical place for a pirate stronghold: near the sea) than it makes sense that still another battle was fought beside this river (the 5th of Nennius’ battles, and the final along the “Dubglas”).

Pursuing the retreating Angles the British have the advantage of cavalry, allowing Arthur to harry the Angle rearguard as they attempt to withdraw south to their stronghold (near modern Boston?). This forces the Angle ceorls at the end of the column to stop and form shieldburg.

We know nothing of “Colgren”. But one didn’t become leader of a band of hardened Germanic warriors except through ability. The Germans followed proven leaders, men whose “word fame” was praised by bards and poets. We can assume that the Angle leader was neither cowardly nor incompetent. Colgren can abandon his rearguard to certain destruction while escaping with the bulk of his forces, or stop and fight. A courageous warrior, he chooses battle.

Again, we have no details of this battle in Nennius; but we can speculate that the Angles would have attempted to take up as strong a defensive position as possible. Perhaps they form their shieldburg in a loop of the river; both flanks securely resting on the bending river.

Arthur waits for the rest of the British forces, following as fast as they were able, to join him. The Britons draw up their Army opposite the Angle position. Arthur places his infantry in the center, his cavalry waiting on either flank. The Britons harass the Angles with arrows and javelins, in late Roman military practice; then close with spear. The Angles’ shieldwall repels the British assault, the levies no match for these hardened Germanic warriors. Then, as the Britons disengage, Colgren’s warriors go over to the offensive. They push hard against the shieldwall of the British infantry, which loses cohesion as it tries to back away; and tactical withdrawal threatens to become rout.

1463994 Hypothetical reconstruction of the Fourth Battle of Dubglas River (Nennius’ 5th Battle)

But as they advance past the safety of the river’s loop, the Anglish flanks are exposed. Horns blare, as Arthur orders both wings of heavy horse to charge! This is also the signal for the infantry to halt their retreat, and hold firm.

Both of the Angles’ flanks are crushed back onto their center by the British cavalry. The flanks crumble, the center soon follows, and the Angles break and flee for their lives.

In the ensuing pursuit, Arthur’s riders hunt-and-harry the fleeing Anglish, riding down the fugitives without mercy! Their blood lust is loosed, and British swords rise and fall like threshers at harvest. Few Angles survive to reach their stronghold; and those that do are too panicked to bar the gates against the close-pursuing Britons.

Colgren’s body is found the next day, drowned in the river while attempting to escape.

These Angles are broken utterly, the survivors surrendering at the discretion of the conquering Britons. Arthur takes the best of the prisoners into his service; the Germanic warriors bending their knee, swearing an oath to Wotan as well as the Christian God to serve Arthur faithfully. (The practice of taking prisoners of war into military service within a successful general’s bodyguard was common in the 5th and 6th century. The concept of nations or national loyalties did not exist in this age of ever-changing alliances, shifting tribal confederations, and ad hoc armies of military adventurers. The warrior class from Persia to Scotland was often quite willing to accept service with whatever successful leader would employ them.) The remaining Angle survivors are allowed to retain their farms as military settlers (foederati), in fealty to Arthur’s ally, the King of Elmet. They will protect this section of coast from their piratical cousins.



  1. Historically, if he existed at all, Arthur most likely occupies the period between the last quarter of the 5th century and the first half of the sixth. I have made the argument in earlier installments that Arthur’s career as Dux Bellorum (warlord of the Romano-British kingdoms) can best be placed in the first decades of the sixth; and his reign as Emperor (Amerawder) between 516 and 535.
  2. In exploring Arthur’s identity, we have explored the possibility that he held land in the south, in Dumnonia. While it is certain he was not the king of Dumnonia, he may have held lands in Triggshire as a vassal of that king. While it may seem strange that the war-leader (Dux Bellorum) of the Celtic British kingdoms might have been at the same time a vassal of one of these kings; such complicated and often contradictory allegiances and subordinations are not without example in history. The Plantagenet kings of England were equals and rivals to the kings of France; even while owing fealty and homage to the French crown for those lands they held in France.
  3. Morris, John, The Age of Arthur, A History of the British Isles from 350 to 650. P. 127. Barnes and Noble Books, 1996
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  1. Pingback: THE AGE OF ARTHUR, PART ELEVEN: CERDIC THE SAXON | The Deadliest Blogger: Military History Page

  2. ritaroberts says:

    Happy New Year Barry. I can’t emphasize enough how much I enjoy reading your posts.This one of course about Arthur is everybody’s favourite. By the way, may I ask if you deliver any lectures on U tube at all about your subject .?

  3. Mike Weatherley says:

    Happy New Year Barry. Actually, just over a year ago, I published a historical novel on just this subject, with Arthur’s first battle being on the Lincolnshire River Glein/Glen. It’s called ‘Pendragon: The Arthur chronicles:1’, and contains much of the research & sources at the end of the novel. You can see some details of my book (wherein I agree with some of the points you make) here:

    • barrycjacobsen says:

      I will certainly look up your writing, Mike! Thanks for the heads-up!

      • Mike Weatherley says:

        Hi again Barry. On the subject of Arthur’s first battle – on the River Glein/Glen (meaning ‘Clean/clear water’ in Celtic) – as you know there are two main candidates. The Northumbria Glen & the Lincolnshire Glen. Many favour the northern one, yet that is only a small tributary of a longer river and lies many miles inland – not the likely site of a battle against seagoing invaders. Also, the Anglo-Saxon settlement of Northumbria was much later than Arthur’s time. However, the Lincolnshire Glen – which many historians seem to overlook – is much further south and within the coastline raided by Saxons for centuries. Hence the presence of the nearby Saxon Shore fortress of Brancaster, on the opposite bank of the great estuary called The Wash. There may actually have been another Saxon Shore fort on the Lincolnshire bank of The Wash during Roman times, at Skegness, but coastal erosion has since removed it. Either way, this is in the right location to be subject to Saxon landings in the 5th c. Another point that historians miss is that the modern Glen may only be a tributary of a larger river (the Welland) today, yet, in Roman times, the estuary of The Wash ran 5-10 miles further inland! And so in the 5th c. the Lincolnshire Glen was not a tributary of the Welland, but would have emptied straight into the sea on the banks of the Wash estuary, somewhere near modern Spalding. Thus it would be just the kind of site where land-based British cavalry could have opposed a Saxon landing! And that is why I site Arthur’s first battle there in my novel (with the evidence for it included in the Author’s Note at the end). Like you, I also locate the site of Arthur’s next four battles, on the river Dubglas (meaning ‘Dark/muddy water’ in Celtic) in the East Anglian region, though that is for the second book in the trilogy 🙂 The first book is currently on a promotion on & also available on

      • barrycjacobsen says:

        Mike, is it your belief that Ambrosius and Arthur were one-in-the-same?

  4. I would like to add my thanks for your blogs, which I value. Thank you for the effort and the time you put in. I know it isn’t easy to achieve!

  5. George S says:

    Hi from Greece !!! I can’t wait for the next chapter ! Your work is amazing !!!

    • barrycjacobsen says:

      Thank you, my Hellenic friend! I traveled for a month through Greece in 1997. Walked many of the battlefields of old. Climatically and topographically Greece is very much like my native southern California.

      The next installment in the Age of Arthur series is in the works. I am finishing an article on the Byzantine defeat at Myriocephalon in 1176 first.


  6. Pingback: THE AGE OF ARTHUR, PART THIRTEEN: ARTHUR’S NORTHERN CAMPAIGN | The Deadliest Blogger: Military History Page

  7. Mike Weatherley says:

    Hi Barry, I only just read your reply, above 🙂 (I did click the request, below, for email notifications, but that function doesn’t seem to be working.) Anyhoo, to answer your question: It was my hypothesis, for seven years on (the now defunct) Arthurnet, that it’s perfectly possible to ‘square the circle’ that confounds most who study this subject. We have evidence for an ‘original’ Arthur in 2nd c. Britain (he being the likely commander of the 5,500 Sarmatian cavalry sent there by Marcus Aurelius in 175 AD (sources quoted in the notes at the end of my book). So he – Lucius Artorius Castus – is clearly the historical prototype for anyone of that name commanding British-based armoured cavalry. However, we have two later historical sources (also discussed at the end of my book) which both refer to a late 5th c. campaign by the (still partly Romanised) Britons against invading Anglo-Saxons (among others). The earlier (and presumably, more reliable) one implies that Ambrosius was the personal name of the British leader during the campaign culminating in the battle of Badon. The later source states that the British leader was ‘Arthur’. Yet if we examine all the above sources (and many others) it is perfectly possible that both the DEB & HB may have been referring to the same person. It may all hinge on the earlier source being aware of the man’s personal name but not his ‘battle name’ and the later source vice versa. Or perhaps Gildas was aware of his battle name, but chose to use his proper name instead. Either way, if you take into account the Notitia Dignitatum and other sources, it’s perfectly possible that the name of Artorius may have survived as the title/battle name of the commanders of the Sarmatian cavalry for 300 years – even if not widely known outside that unit itself. As for the Roman army units in Britain still surviving there through the 5th c., that’s perfectly possible considering the latest possible dating of the N.D. and the recent well-argued debunking of the notorious passage in Zosimus (which is the only reliable one used for claiming that Britain was denuded of ‘Roman troops’ in the 5th c.) In fact, that entire chapter of Zosimus is referring to the Gothic invasion of Italy, and to the province of Bruttium – not Britain at all. Plus we have archaeological evidence for several Roman forts in the north of Britain being repaired and remaining occupied long after the erroneous date for the abandonment of Britain of 410 AD. But as the saying goes: ‘All is explained within the pages of my book’ – if you read it from cover-to-cover. 🙂

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