Isca Dumnoniorum but seems to have gone into decline prior to the Roman withdrawal from Britain . The name "Isca Dumnoniorum" is a Latinization of a native Brittonic name describing flowing water, in reference to the River Exe. More exactly, the name seems to have originally meant "full of fish" (cf. Welsh "pysg", "fish"), although it came to be a simple synonym for water (cf. Scottish whiskey). This is also reflected in the modern Welsh name for Exeter: "Caerwysg" meaning "fortified settlement on the river Uisc". The same name was used for the River Usk (modern ) in southern Wales, causing the
Isca Dumnoniorum Fosse Way, and on the 7th-century Ravenna Cosmography, where it appears as the apparently confused entry of . The fortress was given up around 75 and shortly afterwards its grounds were converted to civilian purposes. The military baths were too large for the local population and were largely demolished, although parts were incorporated into the forum and basilica built on the site. A smaller bathhouse was then built to the southeast. In the late 2nd century, the ditch and rampart defences around the fortress were replaced by a bank and wall enclosing a much larger area, some 92 acres (37