I live in Somerset but I don't come from there. I come from the place of the Mercia tribe, Brum, although I am not descended from Mercians as they were defeated by one or more invading armies (Romans, Vikings, Mid-Europeans) and legged it to the hills of Wales and Scotland. So I am descended from those cowardly Mercians who remained to inter-breed with the invading armies as life settled down.
'Cept I'm not. Because my surname, so the records show, was changed from Tillé to Tilley because the Cornish couldn't cope with writing the name of the French labourers who had pitched up looking for work in the seventeenth/eighteenth century.
Now I would be guessing at this point, but population movement probably didn't make those immigrating-folk pure Breton. Frankly their record-keeping was a sack of pants (dirty) so I can't say with certainty. Italy? Spain? North Africa? Anyway they were all joined up once (a bit before people came along, I accept) and international boundaries still cause the odd dispute, you may have noticed.
Please help me. To where would you like me to return?