Armorica or Aremorica is the name given in ancient times to the part of Gaul that includes the Brittany peninsula and the territory between the Seine and Loire rivers, extending inland to an indeterminate point and down the Atlantic coast. It is based on the Gaulish phrase "are mori" "on/at [the] sea", made into the Gaulish place name Aremorica 'Place by the Sea'. In Breton (which with Welsh and Cornish are the living representatives of Gaulish), 'on [the] sea' is 'war vor' (Welsh 'ar for'), though the older form 'arvor' is used to refer to the coastal regions of Brittany, in contrast to 'argoad' (ar 'on/at', coad 'forest' [Welsh 'ar goed' ('coed' forest)] for the inland regions. This modern use suggests that the Romans first contacted coastal people in Britanny and assumed that the regional name Aremorica referred to the whole area, seaside and inland.
The Irish form is 'ar mhuir', the Manx is 'er vooir', and the Scottish form 'air mhuir', however in these languages the phrase means 'on the sea', as opposed to 'ar thír' or 'ar thalamh/ar thalúin (er heer/er haloo, air thìr/air thalamh) 'on the land'.
Pliny the Elder, in his Natural History (2.17.105), claims that Armorica was the older name for Aquitania, stating Armorica's southern boundary extended to the Pyrenees. Taking into account the Gaulish origin of the name, this is perfectly correct and logical, as Aremorica is not a 'country name', but a word that describes a type of geographical region - a region that is by the sea. Pliny lists the following Celtic tribes as living in the Brittany peninsula: the Aedui and Carnuteni as having treaties with Rome; the Neldi and Secusiani as having some measure of independence; and the Boii, Senones, Aulerci (both the Eburovices and Cenomani), the Parisii, Tricases, Andicavi, Viducasses, Bodiocasses, Venelli, Coriosvelites, Diablinti, Rhedones, Turones, and the Atseui.
Trade between Armorica and Britain, described by Diodorus Siculus and implied by Pliny  was long-established. Because, even after the campaign of Crassus in 57 BC, continued resistance to Roman rule in Armorica was still being supported by Celtic aristocrats in Britain, Julius Caesar led two invasions of Britain in 55 and 54 in response. Some hint of the complicated cultural web that bound Armorica and the Britanniae (the "Britains" of Pliny) is given by Caesar when he describes Diviciacus of the Suessiones, as "the most powerful ruler in the whole of Gaul, who had control not only over a large area of this region but also of Britain (De Bello Gallico ii.4). Archaeological sites along the south coast of England, notably at Hengistbury Head, show connections with Armorica as far east as the Solent. This 'prehistoric' connection of Cornwall and Brittany remained very close as long as Cornish (a dialect of Breton) was spoken. Still farther East, however, the typical Continental connections of the Britannic coast were with the lower Seine valley instead.
Archeology has not yet been as enlightening in Iron-Age Armorica as the coinage, which has been surveyed by Philip de Jersey (Coinage in Iron Age Armorica 1994, vol 2 of Studies in Celtic Coinage).
Under the Roman Empire, Armorica was administered as part of the province of Gallia Lugdunensis, which had its capital in Lyons. When the Roman provinces were reorganized in the 4th century, Armorica was placed under the second and third divisions of Lugdunensis. After the legions retreated from Britannia (407) the local elite there expelled the civilian magistrates in the following year; Armorica too rebelled in the 430s and again in the 440s, throwing out the ruling officials, as the Romano-Britons had done. The "Brittany" peninsula came to be settled with Britons from Britain during the poorly documented period of the 5th-7th centuries. These settlers, whether refugees or not, made their presence felt in the naming of the westernmost, Atlantic-facing provinces of Armorica, Cornouaille ("Cornwall") and Domnonea ("Devon"). These settlements are associated with leaders like Saints Samson of Dol and Pol Aurelian, among the "founder saints" of Brittany.
Questions of the relations between the Celtic languages of Britain— Cornish and Welsh— and Celtic Breton are far from settled. Martin Henig (review, 2003) suggests that in Armorica as in sub-Roman Britain, "there was a fair amount of creation of identity in the migration period. We know that the mixed, but largely British and Frankish population of Kent repackaged themselves as 'Jutes', and the largely British populations in the lands east of Dumnonia (Devon and Cornwall) seem to have ended up as 'West Saxons'. In western Armorica the small elite which managed to impose an identity on the population happened to be British rather than 'Gallo-Roman' in origin, so they became Bretons. The process may have been essentially the same." There is plenty of evidence in the languages and so on of much continuity in those British-speaking areas from before Roman periods.
With western Armorica having already evolved into Brittany, when Vikings or Northmen settled in the Cotentin peninsula and the lower Seine around Rouen in the 9th and early 10th centuries, and these regions came to be known as Normandy, the name Armorica fell out of use.
- Barry Cunliffe, "Britain and the Continent : Networks of interaction"
- Martin Henig, review in British Archaeology 72 (September 2003)
- An Tour Tan- Dorioù Breizh – Breton culture and traditions
- Gouelioù Breizh - Breton events
- Skingomz e Breizh – Breton broadcasting - e brezhoneg hag e galleg - in breton and french
- Sevenadur ha gizioù Breizh e saozneg - Breton culture and traditions in english
- Skol uhel ar vro – High Institute of Brittany - Ti Istor Breizh – The house for the History of Brittany
- Ofis ar brezhoneg - Breton language office
- Banniel Breizh – Brittany’s flag
- Personelezh Breizh e saozneg - Breton identity in english
- Keleier Breizh – Brittany’s news*
- Keleier diwar-benn Breizh – News about Brittany
- Dorioù Breizh - Breton culture
- Douaroniezh Breizh – Geography of Brittany
Wikipedia contributors, 'Armorica', Wikipedia, The Free Encyclopedia, 22 January 2006, 17:46 UTC,