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)
Started life as the canabae outside the fortress of Legio II Augusta.
|Voliba+||Currently unidentified. Fancifully associated with Golden, near Probus in Cornwall.|
|Uxella||(Launceston, Cornwall) - Named Uxella in 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 Ravenna Cosmography. Evidently a settlement on the River Tamar, though not positively identified.|
|Isca||(Exeter, Devon) - The cantonal capital (see above).|
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.