Dumnonia
The kingdom is named after the Dumnonii, a British Celtic tribe living in the south-west at the time of the Roman invasion of Britain, according to Ptolemy's Geography.
Variants of the name Dumnonia include Domnonia and Damnonia, the latter being used by Gildas in the 6th century as a pun on "damnation" to deprecate the area's contemporary ruler Constantine.
[4] Following a period of emigration from south-western Britain to north-western Gaul (Armorica) in the 5th and 6th centuries, a sister kingdom (Domnonée in modern French), was established on the north-facing Atlantic coast of the continent in the region that was to become known as Brittany.
Julius Caesar's Commentarii de Bello Gallico, Book III notes the close trading and military relationship between the continental Veneti of Armorica and the south-western insular British.
There were important monasteries at Bodmin and Glastonbury; and also Exeter where 5th-century burials discovered near the cathedral probably represent the cemetery of the foundation attended by Saint Boniface (although whether this was Saxon or Brythonic is somewhat controversial).
[12] Most of Dumnonia is notable for its lack of a villa system[a] – though there were substantial numbers south of Bath and around Ilchester –, and for its many settlements that have survived from the Romano-British period.
As in other Brythonic areas, Iron Age hillforts, such as Hembury and Cadbury Castle, were refortified in post-Roman times for the use of chieftains or kings, and other high-status settlements such as Tintagel seem to have been reconstructed during the period.
[20][21] Exeter, called Caer Uisc in Brythonic, was later the site of an important Saxon minster, but was still partially inhabited by Dumnonian Britons until the 10th century when Æthelstan expelled them.
[23] It has been suggested that the rulers of Dumnonia were itinerant, stopping at various royal residences, such as Tintagel and Cadbury Castle, at different times of the year, and possibly simultaneously holding lands in Brittany across the Channel.
In 577 Ceawlin of Wessex's victory at the Battle of Deorham caused the Britons of Dumnonia to be cut off by land from their Welsh allies, but since sea travel was not difficult this may not have been a severe loss.
[27] According to the Flores Historiarum, attributed incorrectly to Matthew of Westminster, the Britons were still in possession of Exeter in 632, when it was bravely defended against Penda of Mercia until relieved by Cadwallon, who engaged and, according to Geoffrey of Monmouth, defeated the Mercians with "great slaughter to their troops".
Boniface self-identifies as Anglo-Saxon by birth (using Anglorum in his letter to the English people)[32] and therefore Exeter may have been under West Saxon control at this time, that is, the late 7th century.
At this time Dumnonia was sufficiently part of the known world for Aldhelm, later bishop of Sherborne, to address a letter around 705, to its king Geraint regarding the date of Easter.
[37] In about 936, according to William of Malmesbury writing around 1120, Athelstan evicted the Britons from Exeter and the rest of Devon, and set the east bank of the River Tamar as Cornwall's border.
However, the Breton regions of Kernev/Cornouaille (Cornwall) and Domnonée (Devon) have well-established histories including entirely separate rulers from Dumnonia in Britain (see Duchy of Brittany).
While Cornwall retained its language and culture, Devon's had significantly diminished by the arrival of the Saxon invaders in the 7th century, almost entirely due to the large-scale migration of Britons from greater Dumnonia to Armorica at the end of the Roman occupation.
[44]The relationship between the new Saxon overlords and the remaining indigenous Britons appears to have been peaceable and many Celtic place-names survive in the county, although not to the extent of that of the neighbouring sub-tribe, the Cornovii, who became modern-day Cornwall.
