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Celtic Kingdoms of the British Isles

Celts of Britain


Post-Roman Britain (Romano-Britons) (British Isles)

The history of the British Isles from the end of the most recent ice age to the formation of the united Anglo-Saxon kingdom forms several stages and covers a good deal of conflict. It starts with the Early Cultures which appear prior to the Iron Age. Then the Celtic occupation of Prydein leads up to the Roman incursions and the creation of Roman Britain.

FeatureSubsequent decline generated the Post-Roman period in which all stories of Arthur are contained, but this also covers the gradual loss of Celtic power in the land and its marginalisation on the western and northern fringes. With the expulsion of Roman officials in AD 409 (see feature link), Britain again became independent of Rome and was not re-occupied.

The fragmentation which had begun to emerge towards the end of the fourth century now appears to have accelerated, with minor princes, newly declared kings, and Roman-style magistrates all vying for power and influence while also facing the threat of extinction at the hands of the various barbarian tribes which were encroaching on the borders from all sides. A British Church was in evidence, with practices which would become increasingly isolated from those of the Roman Church.

Various units of laeti and foederati had been settled in the country from the mid-fourth century onwards (probably following the sudden visit to Britain by Emperor Constans in 343). Often Germanic in origin, by 409 they had been settled for up to sixty years and more, and may not have retained much of their 'Germanness' except that they often lived in self-sustaining communities outside city walls. The country was probably filled with similar immigrants from all over the former empire: Danubians, Gauls, Iberians, Italians, and others, many of them the descendants of legionnaires and all settled for some time. By now they were part of the very fabric of the country.

However, as Edward Dawson confirms when backing up the 'Germanness' point above, later units of laeti may not have been so settled. There appears to have been large numbers of them around many towns in the south-east of Britain. Amongst all the empire's immigrants, it was Germanic groups who best retained their cultural identity, sometimes for generations, continuing to teach their children German when others were learning Latin, or perhaps native British. When fresh waves of Germans arrived, conquering all in their path, it was probably not hard for the settled Germans to experience a tactical change of loyalty.

New states which appeared in Britain - and in some cases disappeared or were consolidated - in the fifth and sixth centuries include Alt Clut, Bernaccia, Bro Erech, Buellt, Caer Baddan, Caer Celemion, Caer Ceri, Caer Colun, Caer Gloui, Caer Gwinntguic, Caer Mincip, Caer Went, Ceint, Cernyw, Cornouaille, Cornubia, Cynwidion, Demetia, Deywr, Domnonia, Dumnonia, Dunoting, Ebrauc, Elmet, Ercing, Ewyas, Galwyddel, Glastenning, Guorthegirnain, Guotodin, Gwent, Venedotia, Lyonesse, Paganes, Peak, Pengwern, Pennines, Rheged, Rhegin, and Vannetais.

The region around Caer Lind Colun may also have been under independent British control for a short time, although this was quickly subsumed by Lindsey. Cadbury Castle may or may not have been a powerbase of some kind. In the west, later tradition would claim the creation of the kingdoms of 'North Wales', 'South Wales', and 'Mid-South Wales'. Subsequent division even of that mass of states formed others which may not be mentioned here, and most were conquered piecemeal during the sixth and seventh centuries.

MapIt may have been in this period in which began to emerge the Welsh concept of Lloegr (shown variously as Lloegyr, Logris, or Loegria). This was a span of territory which was roughly analogous to modern England south of the Humber, and was remarkably similar to the civilian-controlled areas of Roman Britain, south and east of the military zones of Wales and the north. This is most clearly shown on the accompanying maps in the AD 70-79 period (see map link).

Could it have been purely a local term used by tribal Britons to refer to those areas which were under Roman law (and in theory remained so under the post-Roman administration) instead of military or royal rule (which covered the north and the western principalities by this period)? The name Lloegr may stem from the Latin 'legibus', which means 'laws', and which was also present in Oscan as 'ligis'. There may not have been a Celtic equivalent as this may have been a new word, something which had not existed when the Celts and Latins shared a common language.

It also has to be wondered just who coined this potentially new name. Was it the Romanised Britons in the south of Britannia who mangled the word 'legibus', or fused it with some Gaulish or Old Brythonic cognate, to form a proper noun which referred to that area of Britannia which was not under military rule or royal tribal rule, and thereby indicating that it was ruled by Roman civil law? This may also have served to give it an air of being a cut above the rough-and-ready north and west. The result could be Lloegr, a word which later entered the Welsh language as the name for England as a whole.

Some of the later post-Roman high kings, accepted as such in other references, are not on the Geoffrey of Monmouth list, so these are shown here in red text. The listing of most of these British high kings was derived by the late Lewis Thorpe PhD from the 1966 translation of The History of the Kings of Britain (1982 Edition used here).

Roman Canterbury

(Information by Peter Kessler, with additional information by Mick Baker and Edward Dawson, from The Landscape of King Arthur, Geoffrey Ashe, from The Anglo-Saxon Kingdom of Lindsey, Kevin Leahy, from The Oxford History of England: The English Settlements, J N L Meyers, from Herefrith of Louth, Saint and Bishop; A Problem of Identities, A E B Owen, from Lincolnshire History and Archaeology, Vol XV, from The Oxford History of England: Anglo-Saxon England, Sir Frank Stenton, from History of the Kings of Britain, Geoffrey of Monmouth, from the Historia Brittonum (The History of the Britons), Nennius, and De Excidio Brittaniae et Conquestu (On the Ruin of Britain), Gildas (both J A Giles, Ed & Trans, 1841, published as part of Six Old English Chronicles (Henry G Bohn, London, 1848)), from the Annales Cambriae, James Ingram (taken from the Harleian manuscript, the earliest surviving version, London, Everyman Press, 1912), from the Life of St Germanus of Auxerre, Constantius of Lyon, from A History of the English Church and People, The Venerable Bede (Leo Sherley-Price translation - revised by R E Latham), and from The Anglo-Saxon Chronicles, Anne Savage (translator and collator, Guild Publishing, 1983).)

409 - c.425

FeatureThis is a period in which central administration apparently breaks down to an extent, with local administrative centres and then rulers beginning to appear. The climb to power of Vortigern of the Paganes seems to reverse this trend (see feature link), although in some regions he probably has to administer what are in effect kingdoms rather than provinces. Even his own territory seems to have been divided into sub-kingdoms, such as Buellt and Guorthegirnain.

Quite possibly, in true Roman fashion, he acquires the title of emperor, perhaps proclaiming himself 'Emperor of Britannia' in order to cement his hold on power. It seems that he and Aurelius Ambrosius of Caer Gloui form the figureheads for opposing parties, but for the moment it is he who has dominance.

Roman amphitheatre at Silchester
This artistic reconstruction shows the amphitheatre at Caer Celemion (Calleva Atrebatum, modern Silchester), which was built outside the walls, to the north-east of the town itself

During this period, mercenaries, or laeti, are settled in some regions of the country, possibly to bolster populations of foederati and laeti which may already have been in place for some generations.

Groups are known to exist along the Thames Valley, in the north of Caer Celemion, and along the Saxon Shore from Caer Gwinntguic to Ceint and Caer Went.

There is a strong economic reason for placing them in the Thames Valley and other lowland areas. Northern coastal Germans (Angles, Jutes, Frisians, and Saxons) are accustomed to employing a farm economy set in lowlands, not uplands. They know how to work marshes and river valleys, so these settlement areas suit them entirely.


FeatureA synod is held in Carthage (the 'Council of Carthage') in the Roman province of Africa which takes a firm line against the Pelagian 'heresy'. Pelagius (circa 354-420 or 440) is a British ascetic who has allegedly denied the doctrine of original sin. He finds many supporters in Britain and the British Church, especially amongst the educated classes (see feature link).

Thames Valley
The Thames Valley forms an east-west passage through the hills between London and Surrey and also through the hills of Wiltshire, providing easy access for river users to the River Avon around Bath


The use of coinage (usually silver coins) as the means of substantial payment seems to die out within ten years of this date. However, a high level of self-sufficiency in both civil service and the army has already become the established norm in Britain for the best part of a century, so this in itself is far from being a sign of the collapse of civilisation.

fl c.420s?

Anblaud / Amlawdd Wledig

Ruler of Ercing. First emperor of independent Britain?


Triphun is the Irish leader of the Déisi in Demetia in the west of Britain. As the fourth generation of Déisi to have been raised in Britain, the tribe now has roots in the country and has clearly developed a certain degree of reliability and trustworthiness.

By taking a Roman name, Triphun has become part of the British ruling elite, so much so that he is able to marry Gweldyr, the Romano-British heiress of Demetia, and become king himself of what becomes known as Dyfed.

fl c.425 - c.455

Wortigernos / Vitalinus / Vortigern

Ruler of Paganes. Second emperor of Britain? Died by fire.


St Germanus, bishop of Auxerre, and Lupus, bishop of Troyes, visit Britain to fight the Pelagian 'heresy' which is running rampant through the British Church. They meet with a still extant Romano-British aristocracy (the principle proponents of the heresy), probably at Caer Mincip. The following year, in line with standard Roman imperial policy in Gaul, Vortigern brings in Saxon allies to help restore order along the borders.

St Germanus of Auxerre
The Alleluia Victory saw St Germanus lead the Britons to a bloodless victory over marauding Saxons, perhaps demonstrating that the country was finally managing its own defence

c.432 - 436

Aurelius Ambrosius of Caer Gloui is apparently a leader of a British council, which presumably answers to Vortigern. It is his decision to confirm the Irish Déisi as commanders of the Demetia area of the west coast in order to counter the threat of Irish raiders.

Vortigern acquiesces and assigns to Ambrosius 'Dinas Emrys and all the western lands', suggesting that Ambrosius becomes the architect for the defence of these western areas.

This is motivated by the council's reluctance to depend entirely upon Saxon mercenaries, with their constant demands for increased provisions, especially in an area in which they will be lightly supervised. The Déisi have already been settled for some time and are already self-supporting.


FeatureAccording to Gildas (see feature link) and Nennius when referring either to Aurelianus Ambrosius (Ambrosius 'the Elder') or his son, this family represents the Romanised nobility in Britain. As already mentioned, they appear to be based in the city of Caer Gloui and its surrounding territories.

They are the main opposition to Vortigern's pro-Celtic faction, and it is at this time that the increasing animosity between the two groups erupts into internecine warfare. The factions fight the Battle of Guolloppum (Cat Guolph, Wallop in Hampshire). The result is uncertain, but it is probably followed by a period of civil strife in eastern and southern Britain.

Romano-Britons burying treasure
With discord building in the country between about 420-450, many Romano-Britons left in a hurry, burying their wealth in the hope that they could return in better times to collect it

fl c.437 - c.446

Ambrosius 'the Elder'

Leader of Romanised opposition in Britain. Killed by plague.

c.440 - 441

Saxon foederati and laeti (settled largely on the east coast and Thames Valley, and probably increased in number since the barbarian raids on Britain of 409) take advantage of the unrest and openly revolt. As a cause they cite the failure of the British to supply them with provisions which may have been reduced to zero as a consequence of the civil war.

By 441, the Gallic Chronicles report large sections of Britain under Germanic control following the Saxon revolt: 'Britain, abandoned by the Romans, passed into the power of the Saxons'.

FeatureCommunications between Britain and Gaul are disrupted, vacated towns and cities are in ruin. The migration of Romano-Britons towards the west and to Armorica turns into a torrent (see feature link), with emigrants coming especially from Dumnonia and Cornubia. The country begins to be divided geographically, along factional lines.


St Germanus' second visit to Britain rids the country of the last of the Pelagian heresy when he visits Elafius' subjects. Elafius seems likely to be the leader of the territory of Caer Gwinntguic. Severe plague hits southern Britain in the same year, and unburied bodies are to be found in the streets of cities such as Caer Ceri.

Post-Roman Londinium
By the mid-fifth century Londinium had been largely abandoned following at least half a century of slow decay and a steadily dwindling population, but with trade virtually ceased the city's purpose was temporarily ended


Former Celtic tribal associations continue to re-emerge as independent territories and kingdoms develop over the course of the fifth century. There is evidence of the reuse and refortification of Iron Age hill forts, while the newly-created kingdom of Brycheiniog creates a capital on a crannog. Cadbury Congresbury in Somerset is producing substantial quantities of Mediterranean pottery, with smaller amounts also coming from South Cadbury as local leaders move their residences to more protected locations.

It is attacks by the Picts (under Drust mac Erp) and Irish Scotti which prompts Vortigern to hire Jutish and Angle mercenaries to fight them off. Hengist and Horsa are invited into Britain and land at Ypwines fleot (Ebbsfleet).

Traditionally, they fulfil the terms of their contract by fighting back the invaders and receive territory on which to settle on the island of Ynys Tanatus (Thanet) in Ceint (although according to British oral tradition, they are first given territory around the Wash and only gain Tanatus after their numbers are swelled by a massive influx of their countrymen).


According to later British tradition, Vortigern is removed from office by the council after trying to settle yet more foreign laeti in Britain, this time in the north-east, within the territory of the 'Kingdom of Northern Britain'. The high kingship is given to his eldest son, the able and popular Vortimer. Hengist, seeing that he no longer has a malleable ally, revolts and the territory or kingdom of Ceint is quickly overrun.

Map of Britain AD 450-600
This map of Britain concentrates on British territories and kingdoms which were established during the fourth and fifth centuries AD, as the Saxons and Angles began their settlement of the east coast (click or tap on map to view full sized)

fl c.455 - 457

Vortimer / Britu

Son of Vortigern. King of Gwent. Elevated by the council.


In the east of the island, the new and more serious foederati revolt sees a loss of territory to Jutes and Angles which is never regained by the Britons. The new arrivals have seen how weak are the British defences and begin a takeover of the kingdom of Ceint, aided by the many foederati settlements in key areas of the land, especially along the Saxon Shore forts and at Canterbury.

They are probably further encouraged by the chaos in Roman Gaul following the murder of the magister militum Aetius. Hengist's polyglot army fights British forces (traditionally commanded by Vortimer) at a place they name Ægelesthrep or Ægelsthrep (probably Aylesford or, less likely, Epsford, both in Kent). Vortimer's brother, Cadeyrn Fendigaid, ruler of the Paganes, is killed, as is Hengist's brother, Horsa.

Again according to later tradition, Vortimer is poisoned and his death allows Vortigern temporarily to reclaim the high kingship before he is faced by Ambrosius Aurelianus. Vortigern flees to his ancestral lands, 'at the fortified camp of Genoreu, on the hill called Cloartius', in Ercing, by the River Wye.

Vortigern meets Hengist and Horsa
Vortigern's policy of hiring mercenaries to help with Britain's defences was entirely in line with those of the late Roman period, but the chaos in the country - plague, mercenary revolt, civil war, frequent pirate raids - probably convinced Hengist and Horsa (shown here being greeted by Vortigern) that land was ripe for the taking

FeatureThere he meets his end when Ambrosius sets fire to his fortress with him inside it. Historically speaking, as much as extremely limited historical knowledge will allow, Aurelianus and his probable successor, Artorius (see feature link), seem to lead the fight to preserve the remaining British territory.

If Vortigern had titled himself 'Emperor of Britannia', then it seems reasonable to assume that his successors copy this, but after Artorius even the grounds for this supposition become reduced.

As if all that isn't enough, in the region of Deywr within the 'Kingdom of Northern Britain', Soemel is noted by the later royal pedigree as someone who 'separated Deira from Bernicia'. It seems to be Soemel who establishes negotiated terms of service, perhaps on a semi-independent basis.

FeatureThis time of chaos and confusion would be an ideal date for this event. At the same time, it would seem likely that Angles from Deywr are settling in Lindsey, which may still be under Romano-British control (see feature link).

fl c.457 - c.480

Ambrosius Aurelianus (Riothamus?)

Magistrate of Caer Gloui. Possible emperor of Britain.

FeatureGeoffrey of Monmouth proposes an almost entirely mythical account of the life of Ambrosius Aurelianus (see feature link). It ends with him being poisoned by Saxons, and his brother, Uther Pendragon, succeeds him.

Roman Aquae Sulis
An artist's impression of Roman Aquae Sulis, later known as Caer Baddan to the Romano-British and which retains that name in an altered fashion today (Bath)

Uther immediately sets out to attack those Saxons who are involved in his brother's death, after they have teamed up with Paschent (Pascent of Buellt), son of Vortigern, and a young nobleman of Ireland named Gillomanius (could this individual be the contemporaneous High King Lóeguire macNéill?).

FeatureUther defeats them all, killing Paschent and Gillomanius. Then Uther has to defeat a resurgent Octa (which scholars think might actually be the real name of Hengist of Kent) before enjoying a largely peaceful reign which leads up to the well-known death of Gorlois of Cornwall and the birth of Arthur Pendragon (with this event, according to legend, taking place in Tintagel, possibly a Dumnonian royal court at this time - see feature link).


After much hard fighting at a place called Crecganford (Crayford in Kent), and apparently heavy losses, the British abandon Ceint. Those Saxons who had joined Hengist in 455 also settle in what is becoming Kent, but they have little impact on the Jutish nature of the kingdom and leave few traces. Some of them instead push farther west to form early elements of the Middel Seaxe.


Occupation of Cadbury Castle is re-established, perhaps selected for its defensive capabilities in these troubled times. Its reoccupation is not in the form of a city or an established seat of government for successive rulers. Instead it seems to be somewhere which a British leader of stature, perhaps Ambrosius Aurelianus, or Riothamus (if they are not one and the same person), makes his personal headquarters.

Cadbury Castle
Even today, Cadbury Castle presents the image of a powerful and defensible location, with views across the whole of Somerset giving it a level of strategic importance

468 - 469

FeatureRiothamus, 'King of the Britons', crosses the English Channel to Gaul, bringing 12,000 ship-borne troops. 'Riothamus' is a title rather than a name, apparently meaning 'supreme king', which raises the possibility that he is Ambrosius Aurelianus (see feature link).

Riothamus remains in the country for a year or more (perhaps reinforced by Armorican Bretons), and advances to Bourges and even farther. Gaul's imperial prefect, the deputy of the Western Roman emperor, treacherously undermines him by apparently dealing with the Visigoths.

Caught by surprise by the Visigoths, Riothamus fights a drawn-out battle near Bourges but is eventually defeated when no imperial forces come to his assistance. He escapes with the remnants of his army into the nearby territory of the Burgundians, never to be heard of again.

A second battle soon follows which involves a combined army consisting of units of Romans, troops from Soissons under Comes Paulus, and Burgundian foederati, but they are also defeated, and Soissons and Armorica are cut off from Rome. The disappearance from history of Riothamus does not rule out the possibility of him successfully returning to Britain, but this would also be a reasonable date for Arthur to take command of Britain's defence as his successor.

Map of Western Europe between AD 481-511
This map shows the expansion of the Frankish kingdom between AD 481-511 and the presence of the Roman domain of Soissons (click or tap on map to view full sized)


Newly arrived Saxons under Ælle and his sons land at Cymens ora and beat off the Britons who oppose their landing (part of the proposed British kingdom of Rhegin), driving them to take refuge in the great forest called Andredesleag (The Weald). These Saxons quickly become known as the Suth Seaxe.

fl c.480 - 511

Artorius / Arthur Pendragon

Son of Uthyr/Uther & Eigr. Possible emperor of Britain.

There is a great deal of material which has been written about Arthur, or more properly Artorius, but there is little direct proof of his existence. For that reason several scholars have chosen to disbelieve entirely in his existence.

FeatureHowever, it seems impossible that an individual who makes such an impact on history that a swathe of later generations of kings name their sons after him, and who is included in a vast body of literature, could not exist. In an historical sense, it seems logical to place him in the last few decades of the fifth century, governing, or at least protecting, the country after Ambrosius Aurelianus and before his traditional date of death in 511 (or 537 by some sources), and perhaps claiming Cadbury Castle as his military headquarters (see feature link).

Traditionally, again, he is the son of Eigr (Ygerna), the daughter of Anblaud 'the Imperator', who has a connection to Ercing. He marries Guinevere, a medieval form of a Cornish name which is probably Veneva (and which descends as the modern Jennifer). She is a princess of Dumnonia, and possibly a sister to King Gerren.

Sir Cligés is one of the less well-known knights of the round table, a poor knight because of his generosity who is rewarded by Uther Pendragon for his kindly ways and selflessness

Artorius himself is primarily a leader of cavalry, the best weapon of the British against the foot-slogging Saxons for as long as they can maintain their breeding stock of large warhorses. This is the force he leads against Geoffrey of Monmouth's Saxon leaders, Colgrin, Badulf, and Chelderic (the first of whom is sometimes linked to Deywr), while being supported by King Hoel of Brittany. This is also how he enters into legend.


Clovis of the Franks defeats, captures and executes Syagrius, the last Roman commander of Soissons. The Franks are now completely dominant in northern Gaul and Roman control has been thrown off. The death of Syagrius may also sends a signal to Saxons and other Germanic peoples that attempting to settle in Gaul is now hopeless, although the situation regarding migrants is hard to determine.


This is the last recorded entry for the Jutes of Kent in the Anglo-Saxon Chronicle until 565. Fighting against the Britons move further westwards as they lose the south coast to the Suth Seaxe, Londinium to the Middel Seaxe and their Suther-ge, and the Upper Thames to the Thames Valley Saxons and Ciltern Saetan (despite the long resistance in the latter area which is offered by Cynwidion and Caer Mincip).

Sir Gawain and the Green Knight
Gawain of the Guotodin is perhaps one of the most famous of Arthur's 'Knights of the Round Table', but his origins seem to lay in the Lothian region, although his actual presence there seems to have been extremely limited

However, the influx of Saxon fighters may have slackened since 460, when the prospects for soldiers of fortune may have seemed better in the remnants of Roman Gaul, coupled with the fact that the Britons are apparently starting to gain the upper hand (especially in the traditional twelve victorious battles of Arthur in locations such as Lind Colun).

Despite this apparent improvement in fortunes, the sense of profound shock which has been dealt to British society by events since the first major Saxon revolt around 441 has triggered changes which will see the rapid mutation of the British language into 'Early Welsh' in the space of about a century.

Young people in this period who grow up with British and Latin languages may be hearing their grandchildren speaking a different tongue. Even the bardic tradition begins to break down, with the sounds and patterns of their words destroyed by the changes. Much of the Iron Age tradition is lost, although fragments do survive.


FeatureAccording to tradition, Cerdic lands in five ships on the south coast at Cerdices ora, together with Saxon and possibly some Jutish companions, and begins a takeover of the local Jutish, Saxon, and sub-Roman territories. Those Jutes and Saxons who are already settled there are apparently already referring to themselves as West Seaxe (possibly separate from the earlier Meonware settlers to their east).

Remains of Roman Canterbury
The Roman city of Canterbury was, by the sixth century, in ruins, with small Jutish houses built in between. The remains of the city wall can be seen all around them

The fighting begins on the same day as Cerdic 'arrives', suggesting that his potential power play begins in violence or immediate resistance. If Cerdic is in fact a Briton who rebels against the remaining central authority (which seems to be a distinct possibility), then given his location he could be serving as a magistrate of the former Belgae territory of Caer Gwinntguic until he seizes part of the territory in order to found his own little empire. It is another blow to British unity and defence.


FeatureArthur seemingly commands the defence of Mons Badonicus against a confederation of Saxon and Jutish warriors which is most likely led by Ælle of the Suth Saxe (see feature link). The British victory grants them a generation of relative peace and consigns the South Saxons to subsequent obscurity. All building and repair work on major new defensive works probably comes to an end with the victory.

There is now a gap in Germanic Bretwaldas for the next half century. This is probably due to the Mons Badonicus defeat and the long peace between the Britons and the Germanic coastal settlements. As there is no significant warfare, there can be no significantly superior war leader to push forward the Germanic advance.

FeatureQuite the opposite, in fact, as there seems to be a reverse migration of Angles and Saxons into continental Europe during the first half of the sixth century. Those who remain are firmly in control of the east (see feature link, right).

Aelle of the South Saxons
The coming of Ælle and his apparently pre-established status as bretwalda spelled eventual defeat and death for the Britons of modern Sussex, and quite possibly led to the siege of Mons Badonicus

Geoffrey of Monmouth has Arthur handing over the kingship to Constantine, but that would presume that the dating shown here is wrong. An alternative date (also given by Geoffrey) for Arthur's retreat to Avalon (Glastonbury in Dumnonia) is 542, which would provide an overlap between Arthur and Constantine, but would displace Arthur's fifth century activity against the Saxons. This revision may only work if his father, Uther Pendragon, actually does exist and has enjoyed the long reign given to him by Geoffrey.

fl c.530 - c.540

Constantine / Custennin ab Cado

King of Dumnonia. Successor to Arthur?


On the other side of the English Channel, the Franks of Austrasia conquer the Thuringians. Portions of territory are lost to Saxons, probably to the Continental Saxons, but there also seems to be a reverse migration of Germanics from the east coast of Britain, where the recent British victory at Mons Badonicus has cut them off from the acquisition of new lands.

These returning Angles and Saxons appear to be given land in Thuringia by King Theuderich. However, it is also at this time, in this century, that the migration of Britons from the mainland to Brittany is at its heaviest, weakening the British defensive position for the future.

fl 540

Aurelius Conanus

King of Caer Gloui.

? - 540

Vortiporus / Vortiporius

King of the formerly client Déisi of Dyfed.


Vortipor(us) of the Déisi of Dyfed is clearly a powerful figure in British history, as noted by his being included in the list of high kings of Britain. His name has been recorded in various ways, from the Latinised Vortipor itself, to the Gaulish Voteporix, and the (perhaps) more genuinely original Vortepor mac Aricol. Even this has been recorded in later Gaelic as Gartbuir mac Alchoil.

Marloes Sands
The coast of Pembrokeshire, part of the territory of the Demetae and the later kingdom of Dyfed, is a mixture of sandy beaches and daunting rocks (as at Marloes Sands, shown here), but there would have been many places for the Déisi to land and seize some territory

fl c.540 - 549

Malgo / Maglocun / Maelgwyn Gwynedd

King of Venedotia.


In the north, the British kingdom of Bernaccia is seized by Angles who have been serving as laeti. The ruling king, Morgan Bulc is forced out. He takes refuge with the Guotodin, shifting his power base there, but the loss leaves a gaping hole in the defences of the eastern coastline. It is the first such breach in the defences of the north, despite a century of such chaos to the south of Britain, and suddenly the defensive strength of the 'Men of the North' looks shaky.

549 - c.600

Following the death of the powerful Maelgwyn of Venedotia, and given the dearth of information about the northern British kings at this time, it is entirely plausible to place first the 'three unnamed tyrants' and then Keretic - see below - as kings in the north.

The Yellow Plague which sweeps through the country hits the Britons far harder than it does the invaders, finally shifting the balance of power in favour of the latter. Even the Picts seem to be affected by the plague, with the possible loss of at least one of their kings, Drust mac Munaith, in 552.

Saxon cremation urns from the area around London
By the mid-sixth century, Saxons were settling around Londinium, and using pots such as these for their cremation burials, while the seax blade is generally more Frankish than Saxon, but the city itself remained overgrown and in ruins for another half a century

It is odd to have such a gap so late in the list, but not if the next four rulers are from the poorly documented north. The Saxon advance in the south also lends weight to this hypothesis (which is proposed by Mick Baker).

Their westwards advance becomes much more rapid, with them soon swallowing much of Somerset and Dorset from Dumnonia. The Angles also advance, taking large swathes of central and northern Britain, and ending any realistic claim by the high kings of Britain to rule over the whole island.

Three unnamed tyrants now claim the high kingship. The names below are accepted as high kings in other references, and their dates fall conveniently into the gap left between the reigns of Malgo and Keretic, but they are not in the list formed by Geoffrey of Monmouth. To differentiate them, they are shown here in red text.

549 - 560?

Morgan Bulc

King of Bernaccia (to 547), and Guotodin (c.560 onwards).


The West Seaxe conquest of Caer Gwinntguic proves that the southern Saxons have recovered from their massive Mons Badonicus defeat. From this point onwards, the Britons continually lose territory until the modern borders of Wales are decided.

Frescoe in Venta Belgarum
A wall painting in the Roman palace of Venta Belgarum as reconstructed by Sean A MacKenna (1932-2012), an expert in excavation, conservation, structure, and restoration

560? - 579

Rhydderch Hen

King of Alt Clut.

579 - 590


King of North Rheged.


Caer Gloui, together with Caer Baddan and Caer Ceri, falls to the West Seaxe. With this collapse, the territory of Caer Celemion to the east is now totally isolated, and Dumnonia is cut off from any overland contact with other surviving British territories (and largely disappears from the overall story as far as the rest of the Britons are concerned).

Gwent and Pengwern now form the western frontier against further Saxon advances. The Hwicce take over the territory and eventually push its borders north into Worcestershire, at the expense of Pengwern.


Ebrauc (York) falls to the Angles of Deira. It is a major blow to British hopes of regaining control of the country and blots out at least two and-a-half centuries of Christian worship in one of the British Church's key bishoprics. It seems likely that, if he exists, Geoffrey of Monmouth's Archbishop Tadioceus of York flees the city with the rest of the nobility, holding his title as an exile, perhaps from Elmet.

590 - 613

Keretic / Keredic / Ceredig

Probably the same Ceretic as in Elmet.


FeatureThe Annales Cambriae (see feature link) records the death of Dynod of Dunoting in battle against the Bernicians. He is probably the last British ruler of the Pennines (unless the remnants of the territory are absorbed into North Rheged).

Gloucester's Roman walls
Despite the focus of settlement now being away from the old fort, Glevum's Roman walls were still very much in use in the sixth century, at least until the city's fall to the West Seaxe

His family are forced to flee to Powys, including his second son, the famous bard, Aneirin, while another son, Deiniol, is already in Gwynedd as the British Church's first bishop of Bangor.

By this time the Deiran and Bernician Angles are pushing far into British territory, and the Iclingas are expanding to the south with only Elmet and the probable Cynwidion and Caer Mincip alliance holding out in this region as enclaves until 616-617, and South Rheged until about 613.


The Gododdin is a long series of elegies composed from the early seventh century onwards which commemorates a force of Britons who assemble in Guotodin at this time. This force marches south to fight the Angles at Catreath and seemingly attacks the Roman fort near the strategic road junction now called Scotch Corner.

Ultimately, the battle is a disaster for the Britons. The flower of the northern British warrior class is decimated by the superior numbers of the Bernicians. Guotodin, as well as the other kingdoms of the north, probably including Elmet, are all fatally weakened by the defeat.

The Mote of Mark
The Mote of Mark is an early hill fort at Rockcliffe, overlooking Rough Firth, which was occupied in the sixth century, presumably by Rheged's nobility


The first meeting takes place between the Roman Church in the form of St Augustine of Canterbury, and the Celtic Church (the descendant of the former British Church of the Roman period). It is arranged when Æthelbert of the Cantware uses the Hwicce as intermediaries, and the meeting goes favourably for Augustine.

A second meeting is quickly arranged, although perhaps not in the same year. This takes place at Abberley in Worcestershire, probably close to the border between the Hwicce and Pengwern. It is attended by seven bishops of the Celtic church, along with many learned monks, mainly from Bangor-is-Coed (in Pengwern).

The meeting ends in disappointment for the Roman envoy, with no agreements of cooperation or unity being reached between the two churches, especially in regard to the important question of the calculations for Easter and evangelising the pagan English.

c.600 - 610

The territory of Caer Celemion is destroyed, probably by Ceawlin of the West Seaxe. It is the last British-held territory south of London and east of Dorset to fall. The town of Calleva Atrebatum is abandoned and its wells are filled in to prevent its citizens from returning.

Lowbury Hill in Berkshire
Caer Celemion's re-use of a former Roman temple at the top of Lowbury Hill (near Compton in west Berkshire) in the mid-500s as a look-out point ended with the territory's fall, but it did see further use as an Anglo-Saxon cemetery

c.610 - 630

FeaturePressure from the Ciltern Saetan to the south and the Middil Engle to the north forces the kingdom of Calchwynedd into collapse around this time. The territory is subjugated by the rapidly growing power of the kingdom of Mercia, which in this period often shows signs of being partially British itself, either in its early ancestry in Britain or in its choice of allies and the people who probably form a good percentage of the population (see feature link).


After Keretic, the high kings are dominant only in Wales and surviving British western territories. However, even contact with territories such as Dumnonia, Elmet, and Guotodin are becoming tenuous, as the lines of communication are cut.

In the first half of the seventh century, the whole of northern Britain is lost, including South Rheged. Direct lines of communication are cut off entirely between the British west and the kingdoms of Alt Clut and Guotodin, and the territory of Galwyddel.

Further tragedy is about to strike for the Britons. In one of the bloodiest and hardest fought battles of its time, several of their kings form a coalition to halt Æthelfrith of Bernicia at the Battle of Caer Legion (Chester). Cearl of the Mercians could also be involved on the British side (according to scholarly theory).

The isle of Lindisfarne, or Ynys Metcaut to the British, remained the fortress by which the Angles held onto their kingdom in the face of repeated British attacks, but Din Guayroi or Guarie (Bamburgh Castle) shown here may have been another

FeatureIago of Gwynedd and Selyf of Powys are both killed, and the battle is a disastrous British defeat (see one of Geoffrey of Monmouth's more accurate entries about this campaign via the feature link). The subsequent Battle of Bangor-is-Coed, however, appears to be a British victory over Æthelfrith.

613 - 625

Cadvan / Catamanus

King of Gwynedd.


Cadwallon (and probably his father, Cadvanr) already holds a claim on the crown of Deira as part of his domains. He now apparently includes Elmet in this claim, following the kingdom's conquest by Edwin of Deira.

625 - 634

Cadwallo / Cadwallon ap Cadfan

King of Gwynedd. Claimed the Deiran crown, including Elmet.

633 - 634

FeatureUniquely, perhaps, Penda of Mercia allies himself not to other English kingdoms but to the Brito-Welsh of the west Midlands and Wales (see feature link). In this year, already working in alliance with Cadwallon, Penda kills Edwin of Bernicia and Deira at the Battle of Hatfield Chase (just outside the western borders of Lindsey).

It seems that, up until this great victory, Penda is the junior partner in the alliance, but following Cadwallon's death in 634 he holds all the cards and is senior partner in the alliance with Pengwern.

Roman Viroconium
The old Roman fort at Viroconium, one of their largest settlements, was substantially and skilfully rebuilt in timber between about 530-570, and then mostly dismantled by 600, during the period in which Pengwern may have achieved a semblance of independent Romano-British rule

634 - 664


King of Gwynedd. Last high king of Britain.


Cadwaladr is probably killed by the great plague which hits the country. There is no obvious candidate to replace him, and such is the extent of the loss of territory over the past century that there is no longer a 'British' Britain over which to claim any high kingship.

Instead, the rival Anglo-Saxon 'bretwaldaship' takes precedence. Kingdoms such as Dyfed, Gwynedd, and Powys remain independent in the west, with Dumnonia in the south-west, and Alt Clut in the far north, but everywhere else the English are in control.

A revised form of the British high kingship later emerges in medieval Wales, but only after centuries of internecine rivalry to work out just who qualifies as a 'prince of Wales'. Gwynedd long remains the strongest kingdom there, rivalled later by Deheubarth. The Anglo-Saxons eventually unite in the face of a massive Viking invasion to form a united Wessex and then a united England.

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