Dumnonii Celtic Tribe

The Dumnonii or Dumnones, were an Iron Age tribe in the British Isles prior to the Roman invasion of Britain. Their territory was in what is now as Devon and Cornwall.

The Realm of the Dumnonii according to Ptolemy

“Next to these [the Durotriges], but more to the west, are the Dumnoni, whose towns are: Voliba 14*45 52°00 Uxella 15*00 52°45 Tamara 15*00 52°15 Isca, where is located Legio II Augusta 17*30 52°45.”

Above quote from the Geographia of Ptolemy (II.ii)

The Dumnonii tribe occupied territories which comprised the modern county of Cornwall and Devon west of the River Exe. The tribe had no pre-Roman tribal centre. Intermarriage with other tribes was uncommon. Strong traditions reaching back to bronze age. Became civilised due to foreign interest in tin mines. Notably friendly to strangers but fiercely combative when threatened.

There are no direct references to the Dumnonii in any of the classical sources apart from Ptolemy, who assigns four poleis to the tribe (see below), only one of which has been satisfactorily identified. His description of the canton is worth quoting in full, primarily because there isn’t much else.

“… Description of the west side … Uxella Estuarium 16*00 53°30; Herculis Promontorium 14*00 52°45; Antivestaeum or Bolerium Promontorium 11*30 52°30; Damnonium or Ocrium Promontorium 12*00 51°30.¹ Description of the south side below which is the Britannic Ocean.² After the Ocrium Promontorium is: the mouth of the Cenio 14*003 51°45; the mouth of the Tamarus 15*40 52°10; the mouth of the Iscas 17*40 52°20; the mouth of the Alaunus 17*40 52°40;³ … [?=]” (Ptolemy Geography ii.2)

  1. Respectively; the River Axe in Somerset, Hartland Point in Devon, Land’s End in Cornwall, and Lizard Point in Cornwall.
  2. The English Channel.
  3. Of the four rivers listed, the first and last mentioned are unknown, the remaining two have been identified with the River Tamar in Devon and Cornwall, and the River Exe in Devon.

The Civitas Dumnoniorum The Principal Tribal Centre

Isca Dvmnoniorvm (Exeter, Devon)

Started life as the canabae outside the fortress of Legio II Augusta.

The Tribal πολεις (Poleis or Settlements)Assigned by Ptolemy

  • Voliba+ Currently unidentified. Fancifully associated with Golden, near Probus in Cornwall.
  • Uxella (Launceston, Cornwall) – Named Uxella in the The Ravenna Cosmography. The name has been identified with the Somerset Axe, though no Roman settlement has so far been identified.
  • Tamara (Plymouth, Devon) – Named Tamara in the The Ravenna Cosmography. Evidently a settlement on the River Tamar, though not positively identified.
  • Isca (Exeter, Devon) – The cantonal capital (see above).

Other Places Named in the Itineraries

  • Nemetostatio (North Tawton, Devon) – The Roman earthwork here may be military, or possibly a tax-collection station. Named in the Ravenna Cosmography.
  • Dvrocornavivm – Named Purocoronavis in the The Ravenna Cosmography, this probably refers to an important native Cornish hillfort, such as Carn Brea.
  • Ictis (St. Michael’s Mount, Cornwall) – An ancient port, trading mainly in tin.
  • Statio Deventiasteno (Nanstallon, Cornwall) – Square military enclosure, apparently associated with the tin workings nearby at Boscarne.

Other Romano-British Sites

  • Topsham (Devon) – Settlement and harbour serving Isca, which was connected via road and river.
  • Taunton (Devon) – Ill-defined Roman settlement.
  • Mount Batten (Devon) – Iron Age tin port, continued in use in Roman times.
  • Plymouth (Devon) – Traces of Roman settlement have been found on the north side of the harbour.

The Dumnonian people continued to build new settlements throughout the Roman period, at sites such as Chysauster and Trevelgue Head, but their style of building was wholly-native in form, with no Romanised features. Evidently, the Dumnonii were set in their ways, and were not to accept Roman influence readily. Near Padstow on the NW coast of Cornwall, a Roman site of some importance now lies buried under the sands on the other side of the Camel estuary, near St. Enodoc’s Church; perhaps the western equivalent of a Saxon Shore Fort.


The primary economic product of the Dumnonii was tin, and the area had been mined since ancient times, and was exported from the ancient trading port of Ictis. The only Romanised building outside of the above-named locales, is that at Magor Farm, Illogan, not far from Camborne, which has been classed as a villa.

References for The Dumnonii

  • The Geography of Claudius Ptolemaeus, trans. by E.L. Stevenson (Dover, New York, 1991);
  • Atlas of Great Britain by the Ordnance Survey (Country Life, 1982);
  • Historical Map and Guide: Roman Britain by the OS (4th Ed., 1990);