Isca Dumnoniorum was a town in the Roman province of Britannia and the capital of Dumnonia in the sub-Roman period. Today it is known as Exeter, located in the English county of Devon.
Excavations in the 1970s and 1980s established the presence of a Roman military fortress at Exeter (constructed around AD55) almost certainly for the Second Augustan Legion. The town grew up around this fort and became prosperous, but started to decline even before the Romans left Britain in the early 5th century.
The city walls of Exeter, of which some 70% survive, still mark the perimeter of the town of Isca Dumnoniorum.
Read more about Isca Dumnoniorum: Early Settlement, Roman Fortress, Civilian Town, Decline, Remains