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 Augusta three permanent legionary fortresses in later Roman Britain and, unlike the other sites at Chester and York, its archaeological remains lie relatively undisturbed beneath fields and the town of Caerleon and provide a unique opportunity to study the Roman legions in Britain. Excavations continue to unearth new discoveries on the extent and nature of the site. One of the most exciting discoveries is a complex of very large monumental buildings outside the fortress between the River Usk and the amphitheatre. This new area of the "canabae" was previously completely unknown. The Brythonic name "Isca" means "water" and refers to the