Dumnonii the origin of the interpretation of Dumnonii as "deep valley dwellers" from his understanding of the Welsh of his time. John Rhys later theorized that the tribal name was derived from the name of a goddess, "Domnu", probably meaning "the goddess of the deep". The proto-Celtic root *dubno- or *dumno- meaning "the deep" or "the earth" (or alternatively meaning "dark" or "gloomy") appears in personal names such as Dumnorix and Dubnovellaunus. Another group with a similar name but with no known links were the Fir Domnann of Connacht. The Roman name of the town of Exeter, "Isca Dumnoniorum" ("Isca of
Celtic language decline in England a "vicus", and others end in elements denoting Roman features, such as "-caster", denoting "castra" ('forts'). There is a substantial body of names along the lines of "Walton"/"Walcot"/"Walsall"/"Walsden", many of which must include the Old English word "wealh" in the sense 'Celtic-speaker', and "Comberton", many of which must include Old English "Cumbre" 'Britons'. These are likely to have been names for enclaves of Brittonic-speakers─but again are not that numerous. In the last decade, however, scholars have stressed that Welsh and Cornish place-names from the Roman period seem no more likely to survive than Roman names in England: 'clearly name loss