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Celtic Kingdoms of the British Isles

Celts of Britain


Caer Ceri / Corinium (Romano-Britons)

FeatureWith 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 from all sides.

FeatureCaer Ceri is the second of the three post-Roman British kingdoms to be mentioned in the Anglo-Saxon Chronicle at the date of their conquest. Caer Ceri (modern Cirencester) in the territory of the Dobunni is a later, Brythonic version of the Roman name of Corinium. Its use in connection with its sixth century fall to the West Seaxe serves to define a territory which probably existed and which had the city at its core.

This territory of Caer Ceri would have been bordered to the west and north by an equally obscure territory which is named here as Caer Gloui. The city at the core of this particular territory appears to have acted as a regional authority which encompassed Corinium until the mid-sixth century. To the east was Cynwidion, while south was Caer Celemion, and to the south-west was Caer Baddan (three more equally obscure Romano-British territories).

Corinium was originally a fort which was established perhaps a year after the Roman occupation of the territory in AD 43. The fort was vacated in the mid-70s and the tribal capital of Corinium Dobunnorum was founded in its place, probably under Roman Governor Julius Frontinus. By the second century the city was one of the largest in Britain, and by the third century it was second in size only to Londinium. The origin of the name is obscure. The Roman name was a Latinisation of an earlier Celtic name, but this remained unrecorded. Some sources suggest it may have been 'Cironion'.

However, the Brythonic language has gone through five stages to reach modern Welsh: 'Primitive' (in the 500s-700s), Old Welsh (in the 800s-1000s), Middle Welsh (in the 1100s-1400s), 'Early Modern' (in the 1400s-1700s), and 'Late Modern' thereafter. Until the 'Middle', the word 'caer' was actually 'cair', from the Brythonic 'cajr', meaning 'fort, fortified place'.

Post-Roman Corinium seemingly emerged as part of a regional division which included much of the upper eastern shore of the Severn and perhaps even the West Midlands, as Vortigern of the Paganes seems originally to have linked the two together. When Corinium was finally conquered by the West Seaxe, the name was retained - but only in a typically mangled fashion - as Cirenceaster (by AD 900 - within the county of Gloucester).

Roman Canterbury

(Information by Peter Kessler, with additional information by Edward Dawson and Trish Wilson, from The Cambridge Historical Encyclopaedia of Great Britain and Ireland, Christopher Haigh (Ed), from The Oxford History of England: Roman Britain, Peter Salway, from Glevum - The Roman Origins of Gloucester, Nigel Spry (Gloucester Civic Trust, 2003), 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 Roman Britain: A New History, Guy de la Bédoyère, from Atlas of British History, G S P Freeman-Grenville (Rex Collins, London, 1979), from The Anglo-Saxon Chronicles, Anne Savage (translator and collator, Guild Publishing, 1983), from A History of the English Church and People, The Venerable Bede (Leo Sherley-Price translation - revised by R E Latham), and from External Link: Cotswold District Council - The Roman Town of Corinium.)


According to Gildas and Nennius when referring to either Aurelius Ambrosius or his son, this family represents the Romanised nobility in Britain. It is possible that by this time, as elsewhere, a magistrate is in charge of the governance of Caer Gloui (and seemingly Caer Baddan and Caer Ceri too, given that the three cities are closely linked). Given the later role of Ambrosius Aurelianus in this region, it seems entirely possible (although hypothetical), that his father now fills this position.

Caer Ceri Roman gates
The Roman gates were still in use in Caer Ceri (Corinium) during the mid-fifth century, although just how long they remained looking this impressive is unclear

Until this decade, the piazza of the forum in Corinium, or Caer Ceri, has continued to be swept clean, demonstrating a clear attempt to retain a degree of civilisation and Roman lifestyle in the town. However, that now ceases and the piazza is abandoned.

The timing may be coincidental, but it is in this decade that the growing rivalry between the two opposition factions in Britain appears to erupt into civil war. The city's amphitheatre remains in use in the early fifth century despite similar structures in other cities falling into disuse. That disuse may be due to perceived anti-pagan legislation.

FeatureCaer Ceri lays in an area which has been most notable for its sustained interest in paganism in the previous century (see feature link for more on this). Such sustained interest may be the very reason for the continued use of this amphitheatre.

c.440 - 446

In the early 440s, in conjunction with Caer Baddan, the city's Roman defences are repaired, including the walls. Flood prevention work is carried out on the Verulamium gate. The amphitheatre finds further re-use when a large timber building is constructed within it. This is associated by archaeologists with late fifth or early sixth century pottery, showing that it probably remains in use for at least the next half a century.

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)

This work possibly takes place after a revolt by the country's Saxon foederati and laeti, causing widespread chaos and temporarily resulting in a loss of control in swathes of the country. That itself seems to occur just before southern Britain is struck by a serious bout of plague, perhaps comparable to the Black Death in scale. Unburied bodies are to be found in the streets of Caer Ceri. The town contracts to the aforementioned timber building and some wooden huts inside the amphitheatre.

c.455 - c.496

It seems likely that the Wansdyke is constructed around this time, possibly in response to further Saxon incursions to the east of Caer Gloui's territories. Groups from the Thames Valley appear to force their way into the western end of neighbouring Cynwidion while further groups from the Middil Engle push through the Vale of Aylesbury to complete the encirclement of that kingdom, exposing Caer Ceri's eastern border in the process.

FeatureAll building and repairs on major new defensive works probably comes to an end with the British victory of Mons Badonicus around 496 (see feature link). Perhaps it is felt, quite rightly, that the threat has been entirely removed for the present.

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


FeatureThe three cities, Caer Gloui, Caer Baddan and Caer Ceri, still apparently form a single kingdom (called Guenet by Nennius). This seems to be partially borne out when Gildas infers that Aurelius Caninus is ruling his kingdom as a single political entity instead of one of three minor states (see feature link).


MapAround this time, either upon the death of Aurelius or his successor in Caer Gloui, the single kingdom which is based there now divides into Caer Baddan, Caer Ceri, and Caer Gloui. This is probably a result of the kingdom being divided between sons, an act which is based on traditional Celtic practice. The act suggests that a true kingship is being practised by this time, rather than the previous Romanised role of magistrate.

? - 577

Condidan / Candidianus / Cyndyddan

Last British king. Killed fighting the West Seaxe.


Caer Ceri's last king is killed as his kingdom fights alongside Caer Baddan and Caer Gloui. All three are defeated by the West Seaxe at the Battle of Deorham or Dyrham. With this collapse, the territory of Caer Celemion to the east is now totally isolated and Pengwern and Gwent are now on the front line. Cadbury Castle is also abandoned around this time, perhaps suggesting an evacuation of its occupants.

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

Corinium, or Cirenceaster as it becomes known to the English by the start of the tenth century, is soon colonised when the majority of this former British territory is subsequently occupied by the Hwicce, who appear to blend as overlords into the native population.

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