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 ha). There is evidence of copper and bronze working. A possible stock-yard has also been identified and Isca was clearly a key market for livestock, crops, and pottery produced in the surrounding countryside. The importance of Isca as a trading centre is demonstrated by the discovery of more than a thousand Roman coins around the city. However, the dates of these coins suggest that the city was at its most prosperous in the first half of the 4th century; virtually no coins dated after 380 have been found, suggesting a rapid decline. Bishop Ussher identified the Cair listed among the