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
Isca Dumnoniorum ha). There is evidence of copper and bronze working. A possible stock-yard has also been identified and Isca was clearly a key market for livestock, crops, and pottery produced in the surrounding countryside. The importance of Isca as a trading centre is demonstrated by the discovery of more than a thousand Roman coins around the city. However, the dates of these coins suggest that the city was at its most prosperous in the first half of the 4th century; virtually no coins dated after 380 have been found, suggesting a rapid decline. Bishop Ussher identified the Cair listed among the