Isca Dumnoniorum settlement there (modern Caerleon) to be distinguished as "Isca Augusta", while the Devonian Isca was called "Isca Dumnoniorum": Usk of the Dumnonians. Exeter began as settlements on a dry ridge ending in a spur overlooking a navigable river teeming with fish, with fertile land nearby. Although there have been no major prehistoric finds, these advantages suggest the site was occupied early. Coins had been discovered from the Hellenistic kingdoms, suggesting the existence of a settlement trading with the Mediterranean as early as . This is disputed however by Prof T P Wiseman who alleges the hoard was not genuine. Following
Isca Dumnoniorum the line between the Isca fortress and Topsham was excavated at the site on Topsham Road in 2010. Initial dating suggests that it was occupied at the same time as the Isca fortress, –75. The settlement () of Isca Dumnoniorum seems to have developed around the Roman fortress. It is one of the four cities () attributed to the Dumnonii by Claudius Ptolemy in his 2nd-century "Geography" and it served as the tribal capital () of the Dumnonii. It was also listed on the late-2nd century Antonine Itinerary, where it forms the southern terminus of route 15 () on the