Dumnonii the British population, suggesting an ancient connection of peoples along the western Atlantic seaboard. The Latin name for Exeter is Isca Dumnoniorum ("Water of the Dumnonii"). This oppidum (a Latin term meaning an important town) on the banks of I River Exe certainly existed prior to the foundation of the Roman city in about AD 50. "Isca" is derived from the Brythonic word for flowing water, which was given to the River Exe. This is reflected in the Welsh name for Exeter: "Caerwysg" meaning "fortified settlement on the river Uisc". Isca Dumnoniorum originated with a settlement that developed around 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)