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 their initial invasions, the Romans established a 'playing-card' shaped fort () at the site around 55. It was the base of the strong Second Augustan Legion () for the next 20 years before they moved to Isca Augusta (modern Caerleon in Wales). Both Iscas were also home to their families as settlements are thought to have grown up outside the fortress gates, especially to the north-east. Buildings within the fortress, such as barracks, granaries, and workship (), were timber structures, the post-trenches of which were excavated in the 1970s in advance of the Guildhall shopping centre development. The only known