Dumnonia until they submitted to the See of Canterbury in the mid-9th century. Parish organisation was a later development of fully Normanised times. Around AD 55, the Romans established a legionary fortress at "Isca Dumnoniorum", modern Exeter, but west of Exeter the area remained largely un-Romanized. Most of Dumnonia is notable for its lack of a villa system, 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
Celtic language decline in England a "vicus", and others end in elements denoting Roman features, such as "-caster", denoting "castra" ('forts'). There is a substantial body of names along the lines of "Walton"/"Walcot"/"Walsall"/"Walsden", many of which must include the Old English word "wealh" in the sense 'Celtic-speaker', and "Comberton", many of which must include Old English "Cumbre" 'Britons'. These are likely to have been names for enclaves of Brittonic-speakers─but again are not that numerous. In the last decade, however, scholars have stressed that Welsh and Cornish place-names from the Roman period seem no more likely to survive than Roman names in England: 'clearly name loss