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Celtic Kingdoms of the British Isles

Celts of Britain


Gangani & Deceangli (Decangi) (Britons)

FeatureIt was the Romans who coined the name 'Gaul' to describe the Celtic tribes of what is now France and Belgium, quite possibly based on an original form of the word 'Celt' itself (see feature link). When it came to the Celts of Britain, the name of the islands itself was used: Prydein (Latinised as Prettania or Britannia). Its collective people were Britons, although not all of them were Celts, let alone the same 'type' of Celts. Successive waves of immigration had left a vague mix of Bell Beaker folk, Urnfield proto-Celts, Hallstatt and La Tène waves, and Belgae, the latest arrivals. By the first century BC these latter people dominated the south and east of the isles.

MapThe Gangani and Deceangli were both warlike tribes, situated in the extreme north of modern Wales where late Iron Age tribal boundaries were even more uncertain than in the rest of Britain. The territory of the Gangani was on the Lleyn peninsula, while the Deceangli territory comprised north-west and north-east Clwyd and northern Gwynedd. The latter tribe was concentrated mainly around hill forts, with a string of them dotted along the length of the Clwydian Range in the eastern part of their tribal territory, from Moel Hiraddug and following along the eastern bank of the river. Another possible fort was at Dinas Dinorwig overlooking the Menai Straits. The Deceangli also possessed a principal tribal centre at Canovium (modern Caerhun in Gwynedd). This was never developed into a tribal capital by the Romans (see the map of most of Europe's tribes around the first centuries BC and AD to view the locations of these two tribes in relation to all other Celts).

The tribes appear to have been split between Ireland and Britain. While in the latter they were called the Gangani and Deceangli, directly across the Irish Sea their cousins were the Concani or Gangani (in the region which later formed part of Leinster). It seems that they may have settled first in Ireland and then migrated to western Britain by the first century BC at the latest, as the name of the 'Lleyn' peninsula seems to be derived from 'Laigin', the older form of Leinster.

It seems possible that the Gangani were a sea-mobile tribe (which many Belgic tribes were at some point in their histories), which would explain their presence both in Ireland and in two areas along the coast of North Wales. If they were indeed sea-mobile, there was a good chance they were third wave Celtic arrivals, similar to the Belgic tribes in the south and east of Britain (notably the Atrebates, Belgae, Cantii, and Catuvellauni).

Once settled in Ireland, part of the tribe migrated again to the Lleyn peninsula. It seems that after this, perhaps only shortly before the Roman imperial invasion, the Gangani in Lleyn appear to have divided yet again, with a splinter group heading eastwards. This group came to be known as the Deceangli, and sooner or later they found the Ordovices tribe intruding between them and their brothers in Lleyn. This is how both parts of the tribe were ordered and settled when the Romans came across them.

FeatureTo back up this assertion of continued migration and splintering, the Deceangli name has a 'de-' prefix which means 'from'. This strongly suggests that it was the Gangani who migrated from Ireland to Wales, and that the Deceangli were an offshoot which itself later migrated farther east. The remainder of the latter's name, '-ceangli', certainly appears to have the same root as the Gangani name. At the end of the first century AD, Tacitus himself records the tribe as the Ceangi or Decangi (translations differ according to source). However, 'Deceangli' would seem to be their real name, as backed up by several later Roman inscriptions.

The Gangani name would seem to link to the modern Welsh 'cangen' (canghennau, cangau, f) (n), meaning 'branch' or 'bough', from the proto-Celtic *kankī-, also meaning branch. Maybe it was linked to the mistletoe cult practice? An educated guess is that the 'g' of Gangani is pronounced as a full 'k' sound, this being the custom amongst today's Welsh. This is not much of a shift from the 'kh' sound of the Welsh 'c' to the full hard 'k'. A second, tentative guess as to meaning for 'Concani' - in addition to 'branch' or 'bough' - works out as follows: 'con', meaning 'with, together with', plus 'can', possibly meaning 'dog, hound'. Perhaps the meaning should translate as 'with the hounds', or 'hound companions'? This does have a similar construction in the name for the Picts of Fife as the 'fairy hounds'. And of course, with these being word-playing Celts, both meanings may be intended.

Ancient Britons

(Information by Peter Kessler, with additional information by Edward Dawson, from The Oxford History of England: Roman Britain, Peter Salway, from Atlas of British History, G S P Freeman-Grenville (Rex Collins, London, 1979), from Histories, Annals, Tacitus, from The La Tene Celtic Belgae Tribes in England: Y-Chromosome Haplogroup R-U152 - Hypothesis C, David K Faux, from Celts and the Classical World, David Rankin (1996), from Geography, Ptolemy, and from Roman Britain: A New History, Guy de la Bédoyère.)

c.350 BC

It is estimated that the second wave of Celtic migrants settles in western Britain (modern Wales) around this time, replacing or absorbing the previous Celto-Ligurian peoples of the Bronze Age. These second wave settlers include the predecessors of the Gangani and Deceangli, an unknown and unnamed people who may bear some relation to the neighbouring Ordovices.

Tre'r Ceiri hill fort on the Llyn peninsula
Tre'r Ceiri hill fort on the Llyn peninsula is a well preserved archaeological site which displays a five-acre fort within which are around one hundred-and-fifty huts, both round and rectangular

1st century BC

The Concani probably arrive in the Lleyn peninsula from Ireland around this time. They force out the original inhabitants, who may be related to the Ordovices, and quickly split into two bodies. The first settles in the peninsula itself where it is known as the Gangani, while the second body, perhaps larger in size, migrates eastwards into the area which is now Clwyd to become known as the Deceangli.

AD 47

The second Roman Governor of Britain, Publius Ostorius Scapula, conducts a campaign against the Deceangli, ravaging their territory and collecting extensive quantities of booty. Only an outbreak of violence among the Brigantes forces the Roman governor to break off his campaign.

However, the Deceangli appear to remain peaceful for a generation afterwards (or too powerful in their hill forts to be successfully attacked), and no Roman forts or towns are built in their territory. There do appear to be trade links and perhaps some Roman working of the lead mines, so some level of cooperation between the tribe and Rome is probably agreed, possibly with the tribe accepting client status.

Map of Britain AD 10
By the end of the first century BC and the start of the first century AD, British politics often came to the attention of Rome, and the borders of the tribal states of the south-east were pretty well known (click or tap on map to view full sized)

51 - 52

Roman Governor Ostorius marches two legions, XIV Gemina and XX, into western Britain (modern Wales), intent on a final face-off against Caratacus and his Ordovices allies. The site of the large-scale battle between the Britons and the Romans is unknown, other than that it lies somewhere along the Severn.

Roman tactics and equipment produce an overwhelming superiority against the Britons. Caratacus' wife and daughter are captured, and his brother surrenders. Caratacus flees northwards via the territory of the Deceangli, seeking safety with the Brigantes while the Ordovices probably suffer heavy casualties and remain subdued for a generation.


A new Roman Governor, Gaius Suetonius Paulinus, attacks Mona (Anglesey), which he describes as having 'a considerable population of its own, while serving as a haven for refugees'. The main incentive for the campaign seems to be the desire to destroy the druids. They have Mona as the centre of their remaining power in Britain (and certainly their last major outpost).

Taking a large number of Roman troops from the rest of Britain in order to carry out this aim (and critically weakening troop numbers in the east), Paulinus forces his way across the Menai Straits and massacres the Deceangli force which opposes his troops, making especially sure to kill the druids, destroy their sacred groves, and cover their altars with the blood and entrails of British captives.

Roman troops attack Mona
The Romans attacked Mona with a level of brutality and ferocity rarely seen elsewhere in their conquest of Britain, such was their determination to wipe out the druids

Before the victory over the Deceangli can be secured, however, Paulinus is forced to abandon the campaign and rush his troops eastwards to deal with the massive rebellion led by the queen of the Iceni, Boudicca.


In 1885 a lead sow dated to this year is discovered deep in river gravel about fifty metres from the present course of the River Dee, at the Roodeye in Chester. Found along with pot shards, some bones and a couple of skulls, the lead sow is inscribed on top with the words 'IMP VESP AVGV T IMP III' (Emperor Vespasian), while the name Deceangli is inscribed along the side.

The find suggests strongly that Romans are working the lead mines in this area, probably with the cooperation of the Deceangli. Several other items are also found before the twentieth century and dated to AD 74-76, all with Vespasian's name on the top and the Deceangli name on the side.

78 - 79

Fresh from inflicting a final defeat and almost complete destruction upon the Ordovices, the Roman Governor, Julius Agricola, continues his campaign by attacking the warlike Deceangli on Mona (Anglesey). Troops are withdrawn from the territory of the Dumnonii to support the campaign, which is driven by the need to achieve a final subjugation of all of the western British tribes. Following Agricola's victory over the Deceangli, the tribe appears to capitulate and settles down to live under Roman rule.

Britons attack the Romans
The invasion of AD 43 was no repeat of the expeditions of Julius Caesar - this time the Romans came in strength and from at least two directions of attack

A string of forts are built throughout the territory to ensure that these wild and hardy Britons remain pacified, with Trawscoed Fort somewhere close to the border between the Demetae and Ordovices (later Ceredigion) perhaps being one of the southernmost of these. Elements of the tribe apparently flee Britain and find refuge with their possible relatives in Ireland.

The tribe has no obvious tribal capital, and one is not built by the Romans (the Civitas Deceangorum hoped for by some scholars), so it would seem that the tribe is governed under Roman military rule. This could take place from the cavalry fort on the Afon Conwy, which becomes the largest Roman military base in the canton.

c.80 - 81

It seems almost certain that the Romans take control as quickly as possible of the lead mining industry of the Deceangli. The Halkyn Hills site in the north-eastern corner of the tribe's territory (in modern Flintshire, immediately west of Chester) is probably already known to the Romans. This area later emerges as the cantref of Tegeingl under Edward I of England. The name is a direct descendant of 'Deceangli'. An even more notable Roman lead-working site is at Pentre Flint.


A new Roman fort is constructed at Bryn-y-Gefeiliau (also known as Caer Llugwy thanks to its location alongside the Afon Llugwy, near Betws-y-Coed). The fort covers a site of about 1.6 hectares and is possibly built on the foundations of an earlier version which may have been created under Roman Governor Julius Agricola perhaps a decade before. Pottery from the later Trajan and Antonine periods is found within its walls.

Roman wall at St Cybi's Church in Holyhead
By the time the Roman wall had been built around the fort in Holyhead (which was later replaced by St Cybi's Church), the Deceangli had long since been defeated


Writing at this time, Tacitus mentions the Deceangli, dropping the 'de-' prefix to call them Ceangli. He mentions the defeat of the Iceni in AD 61 which had caused all other possibly rebellious British tribes to fall silent. Any attempt at resistance is punished heavily.


After an apparent period of abandonment at the end of the previous century, Trawscoed Fort is permanently abandoned by the Romans, probably no longer needed now that the region is at peace. The Bryn-y-Gefeiliau fort also appears to become abandoned in this period, as suggested by a lack of pottery finds there.


Ptolemy assigns much of northern and central Wales to the Ordovices, but he also mentions the Gangani tribe which occupies the Llyn peninsula. He calls this area the 'promontory of the Gangani'. However, Ptolemy fails entirely to mention the Deceangli, so is he aware that both names may refer to the same tribe and simply discards one name as being unnecessary? The Gangani portion of the tribe are probably kept in check by the Roman fort of Pen Llystyn.


By now the territory of the Deceangli has a sprinkling of Roman villas and is relatively settled. The tribe does not have a chance to re-emerge at a time in which Roman central authority in the west of Britain is fading earlier and faster than elsewhere.

Romano-Britons burying treasure
With discord building in the country (and reaching a peak between about 420-450), many Romano-Britons began leaving in a hurry, burying their wealth in the hope that they could return in better times to collect it

Under constant threat by waves of Irish raiders, the tribe's lands are incorporated along with much of those of the Ordovices into a new territory when Cunedda Wledig and his branch of Romanised Venicones are transferred from the Manau dependency of the Guotodin to secure North Wales from the raiders. They are extremely successful, and the kingdom of Venedotia is formed by them.

Eastern areas of the Deceangli territory later form the cantref of Tegeingl, which preserves the Deceangli name. It becomes part of Mercia during the eighth century and then part of the earldom of Chester. Today it forms part of Flintshire. Links with its Celtic past remain. The surname Craddock is a preservation of the name Cara Dag, which means 'beloved of [the god] Dagda'.

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