History Files

Celtic Kingdoms of the British Isles

Celts of Britain


Caer Gloui / Glevum (Romano-Britons)

FeatureThe Romano-British city of Caer Gloui had been founded by the Romans as Glevum (modern Gloucester). It was first settled around AD 49 as a legionary fort, and a city grew up around it. During the fourth century it probably served as the capital of the province of Britannia Prima within the Diocese of the Britains, and it seems to have retained its importance into the fifth century. While the later name of Caer Gloui is used here, the name of the territory itself has not survived, and in the fifth century the city may instead have been known as Glouvia.

Central administration of Britain appears to have broken down in the mid-fifth century, to the extent that the regions began to establish partially or wholly independent districts or kingdoms. The administration at Caer Gloui found itself in command of much of the land around the mouth of the Severn, which also encompassed the cities of Caer Baddan and Caer Ceri to the south, essentially making it a successor to the former Dobunni tribal territory. In the sixth century, the Romanised district evolved into a kingdom, and its fall is noted in the Anglo-Saxon Chronicle. The incoming Hwicce who took control of the area maintained the city's name, mispronouncing it in their very individual Teutonic language, so that it survives today. Romano-British Glou became Saxon gloe added to -cester from the Latin castrum (fort), emerging as Gleawanceaster (Gloucester).

FeatureJust about all the (extremely scanty) information we have about the post-Roman city and the events of the sixth century comes from Gildas' De Excidio Britannia, Nennius' Historia Brittonum, and Geoffrey of Monmouth's Historia Regum Britanniae, plus a little from Bede. While Gildas and Bede can be said to be reliable, Nennius seems to be less so, and Geoffrey is prone to wild flights of fancy while still retaining a distinct foothold in events that must have been recorded by sources earlier than him.

Vortigern has a claim on the region as a power base until his fall in the mid-fifth century. After that, it seems highly likely that Caer Gloui was one of the centres of operations for Ambrosius Aurelianus during his battles against the Saxons in the south. It is possible that his father also called this territory home. Descendants of the two men seem to have based their claim on the later kingdom on this, if Ambrosius himself didn't specify their continued rule in the city, which is a possibility.

(Information by Peter Kessler, with additional information by Edward Dawson, 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, 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 A History of the English Church and People, The Venerable Bede (Leo Sherley-Price translation - revised by R E Latham).)

c.410 - c.446

Aurelius Ambrosius (the Elder)

Roman senator and pro-Roman. Killed by plague.

c.410 - 418

FeatureAurelius Ambrosius is the official representative of Roman Emperor Honorius to the British provincial council and is claimed as a prince, marking him out as a member of the Romano-British nobility. The country is reorganising at this time, following the expulsion of Roman administration, but links with Rome are clearly being maintained.

c.418 - 425

This period is said to witness the increasing influence and power of Vortigern of the Pagenses, culminating in his high-kingship. The provincial council decides, and external factors dictate, the need for strong, central, leadership in the country, and the impression is that Aurelius Ambrosius is not strong enough to offer a viable alternative. It seems that he and Vortigern form the figureheads for opposing parties, but for the moment it is the latter who has dominance.

c.432 - 436

Aurelius Ambrosius is apparently a leader of a British council, which presumably answers to Vortigern. It is his decision to confirm the Irish Deisi as commanders of the Demetia area of the west coast to counter the threat of Irish raiders. Vortigern acquiesces and assigns 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 on Saxon mercenaries, with their constant demands for increased provisions, especially in an area were they would be lightly supervised. The Deisi have already been settled for some time and would be self-supporting.

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


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.

FeatureAmbrosius (the Elder) has long been Vortigern's main rival, with it seeming likely that they not only head two opposing factions in the country, but also opposing ideologies, with Ambrosius retaining his Romanised, Roman Church background while Vortigern is leader of the Pelasgian pro-Celtic party. Around this year, internecine warfare breaks out between the two rival factions, resulting in 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.

c.440 - 443

In the early 440s the Saxon foederati and laeti revolt, causing widespread chaos and temporarily controlling swathes of the country. Soon after this, the defences of both Caer Baddan and Caer Ceri are repaired. In the latter, flood prevention work is carried out on the Verulamium gate.


Serious plague hits southern Britain and unburied bodies are to be found in the streets of Caer Ceri. The town contracts to some wooden huts inside the amphitheatre.

It is this point at which Ambrosius the Elder, who must be an old man in his sixties, also dies, 'in these same broils', ie. the Saxon revolt, although according to tradition it is the plague which actually claims him. Ambrosius' surviving family is in hiding by now (traditionally in Armorica), avoiding the vengeful clutches of Vortigern. An archaeological excavation at a site in modern Gloucester produced an early fifth-century secondary burial in a Roman funerary building with indications that the man had been of high rank. Could this have been Ambrosius the Elder?

446 - 455

At the same time as the Anglo-Saxon mercenaries in the east revolt (in 455), the entrance to Caer Gloui's amphitheatre is reduced in size to make it easier to defend, and life continues, as evidenced by fifth and sixth century pottery.

Nemausus (Nimes)
Times were tough in the mid-fifth century, and Britain's resources were not what they had once been, what with barbarians at the door and withdrawal from the fading Roman empire, so Caer Gloui's amphitheatre had to be made defendable (Nemausus (Nimes) amphitheatre is shown here)

There is a gap in what can be pieced together of the story at this point, with Ambrosius Aurelianus, the son of Ambrosius the Elder, not emerging into British affairs until perhaps 455 or 460. Given the period at which he appears to be at his most influential, his date of birth is probably around 430, making him too young to succeed his father immediately as a possible magistrate of Caer Gloui, so it seems likely that someone else, a possible deputy or one of Vortigern's supporters, assumes command.

c.446 - c.455?


Name unknown, possibly a deputy of Aurelius Ambrosius.

c.455 - c.480?

Ambrosius Aurelianus

FeatureSon of Aurelius Ambrosius. Magistrate? High King?

c.455 - c.496

Ambrosius (and perhaps the elusive Arthur after him) seems to base himself in the territory of Caer Gloui. Amesbury (which in a Saxon charter of about 880 is spelled Ambresbyrig, 'the stronghold of Ambrosius'), located on the territory's eastern borders, is perfectly suited to be the focus of Ambrosius' military operations. He probably governs the territory as a Roman magistrate rather than as a princeps or king (although he is claimed as the first king by later chroniclers).

It seems likely that the Wansdyke is constructed around this time, possibly in response to further Saxon incursions to the east. 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. There is the possibility that during this period Glevum's residents leave in some numbers to head to Cernyw, on the other side of the Severn, although the connection is tenuous apart from the change in that kingdom's name to Glywyssing around 470-480.

FeatureAll building and repair work on major new defensive works probably comes to an end with the British victory of Mons Badonicus around 496, with the siege possibly being fought outside Caer Baddan.


Name unknown.


The city shows modest re-growth now that peace has been won, and later archaeology shows that a new north gate is created in the city's walls at the beginning of the sixth century. The old gate is now ruined and blocked. However, by this time, the old city is in a very run-down state, and new building work is only in wood. The focus of settlement seems to be nearer the river, away from the Roman city which has suffered from assault and plague during the previous century.


Name unknown.


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.

fl 540

Aurelius Caninus

High King. Named by Gildas. Still ruled the united three cities?


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

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


Name unknown.


The name of the last king is rather remarkable in that it breaks down as 'Con' meaning 'dog' and 'mail/fael' meaning servant. Speculatively speaking, this 'dog servant' may have links to the kings of Glastenning to the south. The king there, Cyndrwyn Glas, is also king of Dogfeilion, which name means 'servant of [the god] Dagda'.

However, a much more likely reason is the sense of humour sometimes exhibited by the Welsh (even today) in naming their offspring. Conmail's grandfather, Aurelius Caninus, may well have been alive at the time of his birth. What better jest than to poke gentle fun at the mostly pagan naming convention of 'Cuno-' ('cyn') added to this or that god than by naming someone just plain 'dog' (Aurelius Caninus, the latter being the Latin for dog), and then in his grandson combining it with the mostly Christian convention of mal/mail/mael?

? - 577

Conmail / Cynfael

Killed fighting the West Seaxe.


Caer Gloui, together with Caer Baddan and Caer Ceri, falls to the West Seaxe following the Battle of Deorham or Dyrham (an event which is rather obtusely doubted by some but which would be entirely in keeping with the pattern of Saxon advance to the west). 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. 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. However, rather than simply sweep away all that is British, they appear to form a new top layer of aristocracy over a largely British population that retains much of what it had before, possibly even down to its church organisation.