Isca Dumnoniorum again around 680 with a document that reporting that St Boniface was educated at the abbey in Exeter. Much of the Roman wall survives as the lower courses or inner core of the medieval city walls, 70% of which still exist, largely built on the orders of Alfred the Great to protect the far west of his kingdom following the Viking occupation of 876. The legionary bath complex was excavated in the 1970s, but because of its proximity to the cathedral it was not practicable to retain the excavation for public view. Artifacts from the excavation, however, are displayed with
Isca Augusta legion was needed to repel a potential invasion from the Continent. The stone from Isca may have been used for building defences on the south coast. There may still have been an occasional military presence as late as the early 4th century, but the fortress was probably later taken over by the people of the surrounding vicus. The basilica of the baths was used as a cattle pen. Recent finds suggest Roman occupation of some kind as late as AD 380. According to the Gildas (followed by Bede), Roman Caerleon was the site of two early Christian martyrdoms in Britain,