Kingdom of Dumnonia

Dumnonia is the Latinised name for a Brythonic kingdom that existed in Sub-Roman Britain between the late 4th and late 8th centuries CE in the more westerly parts of present-day South West England. It was centred in the area of modern Devon, but also included modern Cornwall and part of Somerset, with its eastern boundary changing over time as the gradual westward expansion of the neighbouring Anglo-Saxon kingdom of Wessex encroached on its territory. The spelling Damnonia is sometimes encountered, but that spelling is also used for the land of the Damnonii, later part of the Kingdom of Strathclyde, in present-day southern Scotland. The form Domnonia also occurs and shares a linguistic relationship with the Breton region of Domnonée. Name The kingdom is named after the Dumnonii, a British Celtic tribe living in the south-west at the time of the Roman invasion of Britain, according to Ptolemy's Geography. Variants of the name Dumnonia include Domnonia and Damnonia, the latter being used by Gildas in the 6th century as a pun on "damnation" to deprecate the area's contemporary ruler Constantine. The name has etymological origins in the proto-Celtic root word *dubno-, meaning both "deep" and "world". Groups with similar names existed in Scotland (Damnonii) and Ireland (Fir Domnann). Later, the area became known to the English of neighbouring Wessex as the kingdom of West Wales, and its inhabitants were also known to them as Defnas (i.e. men of Dumnonia). In Welsh, and similarly in the Southwestern Brythonic languages, it was Dyfneint and this is the form which survives today in the name of the county of Devon (Modern , , ). There is evidence, based on an entry in the Ravenna Cosmography, that there may have been a sub-tribe in the western part of the territory known as the Cornovii from whose name the first element of the present-day name of Cornwall is probably derived. Following a period of emigration from south-western Britain to north-western Gaul (Armorica) in the 5th and 6th centuries, a sister kingdom (Domnonée in modern French), was established on the north-facing Atlantic coast of the continent in the region that was to become known as Brittany.