In the 5th and 6th centuries there was a mass migration of people from Cornwall to the region of France known as Armorica, modern day Brittany and Normandy. Although Cornwall’s deep connections with Brittany are well known, this piece of history is still shrouded in mystery.
Like the Welsh and the Cornish the Bretons are ethnically Celtic and consider themselves one of the six celtic nations. Consequently Cornwall and Brittany really do have much in common. Our languages are closely related, our coastlines look so similar and Brittany even has its own St Michael’s Mount! But the connections go far deeper than this.

Mont Saint Michael, Normandy
The Celtic Connections
Cornwall and Brittany have always traded, especially in tin, for thousands of years. But more than that, there are also deep prehistoric connections. Back in the mists of time it seems likely we had the same ancient ancestors. You only have to look at the similarities between the ancient monuments found in France and those here in Cornwall. And I have also heard it said that the Cornish are genetically and linguistically more closely related to the Bretons than they are even to the Welsh.

The Coasta Rouge Dolmen or Quoit found near Lodeve, France
So the movement of people between the two regions probably goes back far further than the 5th century. Armorica is an ancient name, perhaps with Latin roots, for the region of France or Gaul that lies between the rivers Seine and Loire. It included what is now the Brittany peninsula and it was to here that the Cornish migrated.
There had been a slow trickle of people moving across the channel since around the 4th century. In fact it is likely that people had always moved freely between the two regions to a certain extent. But the numbers grew significantly in period of history known as the Dark Ages. The reason for this mass movement of people, mostly from Cornwall, Devon and West Wales, isn’t clear. Some say that the Cornish Celts were trying to escape the Saxons who were aggressively invading their homeland from the north.
A Flood of People
Whatever the causes, large numbers of people made the crossing from Cornwall to mainland Europe and to begin a new life there.

Cornwall’s Lands End
Records for this time are practically non-existent but we do know a little from the writings of Procopius. Although merely recording tales that he had heard of distant lands he had never seen, Procopius writes that there was a huge movement of people from an island known to him as Brittia to the Frankish mainland in around the 5th century.
It is thought that amongst the hundreds, possibly thousands, fleeing Cornwall there were a number of Cornish princes. These settlers must have been reasonably welcome in their new home as they quickly created two new kingdoms in Armorica which were known as Cornouaille and Domnonea. Names that of course sound very familiar to us today and surely relate to modern day Cornwall and Devon.
The Prince of Cornouaille
It is thought that Cornouaille was founded by Rivelan Mor Marthou, one of the first Cornish princes in the region but no real records of this exist. The name Cornouaille is said to have its roots in the name of an ancient Brythonic tribe. Latinized as Cornovii, it means “peninsula people”, from the Celtic “kernou“, meaning horn or headland. And the name is cognate with, has the same root as, the Cornish name for Cornwall, Kernow.

Vannes, Brittany, once part of Armorica
The region has a complicated history, and you can find more detailed information HERE. Gradually the Armorica evolved in to the regions now known as Normandy and Brittany. And the area’s connections with Cornwall became almost entirely forgotten. But the echoes of those connections I believe continue to this day. Like the Cornish, the Bretons are fiercely independent and passionate about their Celtic culture.
In a time when the world seems determined to return to isolating individualism it is time we thought more about what draws us together, what connects us. Rather than what divides.
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Further reading
Wartime Cornwall – a Haven for the French resistance & Europe’s refugees
The Giant’s Crossing – Statue of Saint Piran, a journey to Brittany
I provide all the content on this blog completely FREE, there's no subscription fee. If however you enjoy my work and would like to contribute something towards helping me keep researching Cornwall's amazing history and then sharing it with you then you can DONATE BELOW. Thank you!
Fascinating read. Thanks for sharing.
Thank you! 😁
Ethically Cornish? Like, with Cornish manners and morals …. ? Sorry, just made me laugh, you missed out the ‘n’ in what I’m guessing should read ‘ethnically’ 😉
Whoops! Thank you for pointing that out!! 😁
Thanks for sharing that. I always wondered about the connection. Did the land used to extend where the Channel now is?(Much earlier, I mean.)
During the ice age it did yes, the English channel only opened up after the end of the ice age
Thanks. I wondered.
Britain was joined to the mainland until around 7,000 years ago, but the last vestige of that was between East Anglia and Holland. The English Channel was the lower Rhine valley with the Seine and Thames as tributaries.
Thanks.
Interesting post, thanks for sharing!
Thank you, interesting view. I think mass migration is misleading. Many people came over to Brittany but in dribs and drabs over hundreds of years and not in an organised movement. Many of the saints came with a handful of followers – St Pol left Cornwall with 12! The language of the incomers merged with native Gallic dialects to form Breton over time.
Brittany is fascinating and I have been photographing its churches, which means I am bumping up against the saints. Some of the photographs will be in an exhibition in Cratfield, Suffolk, on 12 and 13 April, if you are travelling. And there will also be a little exhibition in Brittany at the end of April. I am thinking of exploring the connections in Cornwall and Wales next – thank you for this post.
Etymologically there is a real problem with the Cornovii tribe in Cheshire / Shropshire
‘Intriguingly, the tribal name Cornovii (or Cornavii) occurs elsewhere in Britain at this time, in the north-west of what is today the English Midlands and in the far north of Scotland in what is now Caithness (there were also Dumnonii or Damnonii in west-central Scotland). This may reflect nothing more than the cultural and linguistic affinities between the various Celtic groups that inhabited Britain, although John Morris in his controversial The Age of Arthur postulates an ingenious theory which has the (Midlands) Cornovii as a fifth-century military unit surviving from the then deteriorating Roman administration. Britain was under pressure from both Irish settlement and Saxon invasion, and Morris suggests that the Cornovii were re-deployed from their Midlands base to Dumnonia where their task was to contain and control the Irish arrival.
Although there is indeed evidence of Irish settlement in post-Roman Dumnonia, the Morris thesis is not widely accepted by archaeologists and early historians, and we may safely conclude that the Cornovii located west of the Tamar were an indigenous people quite separate from their namesakes in the Midlands and Caithness’.
Payton, Philip. Cornwall: A History: Revised and updated edition . University of Exeter Press. Kindle Edition.
BTW did you take that top photo?
The movement of people between the two could go back a very long way
That there was a 5th century and later colonisation of Brittany (and Galicia in the NW tip of Spain) from the SW British kingdom of Dumnonia (Cornwall & Devon) is well known, but there were no internal pressures that far west to cause anyone to “flee”. The reason has been mysterious except……. The Atlantic Seaways trading network was millenia old and, by Caesar’s time, was controlled by the Veneti of Southern Brittany. The Roman invasion of that area, and later of Britain, interrupted those Seaways for 400 years by taking full control of all trading, so when the Roman legions finally withdrew, it was open for some entrepreneurs to get the old Seaways up and running again. This, I think was the reason for the colonisations. The entrepreneurs were Dumnonian and, by occupying the two most strategic points on the route, the NW tips of Gaul and Iberia, could take over control. The Seaways most certainly resumed. There are strong indications that the control centre of the Atlantic Seaways, for a while, was Tintagel, maybe in the 6th and 7th centuries, and after Tintagel’s decline as a power-centre c.700, control of the Seaways shifted to Vigo in Galicia. There was still a British bishopric there in the 9th century!
I was born in Brittany and got my DNA tested to verify that science can confirm what the history manuals say. I got tested by 2 companies LivingDNA and 23AndMe and both confirmed that I was 92% Irish and British. LivingDNA was very detailed: I am 15% Irish, 10% from Cornwall, 15% from Devon, 15% from South England, etc…for a total of 92%
Wow, fascinating! I’ve always fancied doing one of those tests!!
I am Breton and did a DNA test: I am 93 % British Island (East Wales, South Scotland and Northwest England) I come from Cornouaille which in Breton is Kernev.
Don’t forget about the comet of 562ad which literally laid low the mountains and burnt the plains and the moors of The Isles. For 11 years the place was uninhabitable those that survived fled.