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 the remains of a Roman harbour had been discovered in Caerleon. Substantial archeologically excavated Roman remains of the Roman fortress can be seen at Caerleon. Cadw administers: The National Roman Legion Museum, located in the village, is part of the National Museums and Galleries of Wales. The museum exhibits artifacts and finds from excavations throughout the village including Roman currency, weapons, uniform etc. In March 2012 an episode of archaeological television programme "Time Team" that had been recorded in Caerleon aired on Channel 4, titled 'Rome's Wild West'. Isca Augusta Isca, variously specified as Isca Augusta or Isca Silurum, was