Isca Dumnoniorum, also known simply as Isca, was a town in the Roman province of Britannia at the site of present-day Exeter in the English county of Devon in the United Kingdom. It served as the tribal capital of the Dumnonians under and after the Romans. The city walls of Exeter (some 70% of which survive) mark the former perimeter of Isca and excavations in the 1970s and 1980s verified that the town was home to a Roman fortress almost certainly for the Second Augustan Legion. The town seems to have grown up around this fort (established ) but seems to have gone into decline prior to the Roman withdrawal from Britain .