The Celtic people
Within 300 years the Celts' territory encompassed much of Europe, extending as far as Anatolia (modern day Turkey) in the east.
As the Celtic peoples dispersed throughout Europe, their settlements became increasingly isolated from one another.
Meanwhile, the Roman civilization was on the rise in the Mediterranean, driving the Celts further west into the British Isles. The shift westward began around 700 BC and continued into the first two centuries AD, when Roman expansion was at its height.
After the Romans left Britain in the 5th century AD, marauding Germanic tribes further isolated the Celts in the north and west of Britain, in the Breton areas of France, and in Celtiberian Spain. These waves of invasion split the Celts into distinct communities.