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
Insula (Roman city) forum around which the most important public buildings would be sited. Insula (Roman city) An insula (Latin for "island") is a city block in an ancient Roman city plan, i.e. one that is surrounded by four streets. The term was also used for apartment buildings that took up an entire city block. A standard Roman city plan was based on a grid of orthogonal streets and was probably founded on the ancient Greek model of Hippodamus and was used when new cities were established, e.g. in Roman coloniae. The main streets of each city would be the Decumanus Maximus (east–west-oriented)