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
Isca Augusta legion was needed to repel a potential invasion from the Continent. The stone from Isca may have been used for building defences on the south coast. There may still have been an occasional military presence as late as the early 4th century, but the fortress was probably later taken over by the people of the surrounding vicus. The basilica of the baths was used as a cattle pen. Recent finds suggest Roman occupation of some kind as late as AD 380. According to the Gildas (followed by Bede), Roman Caerleon was the site of two early Christian martyrdoms in Britain,