Quote Originally Posted by Maeran
Since all the more recent books on the subject that I've read (all popular books, I'm not an expert on the subject and do not pretend to be) distance themselves from the idea of successive invasions (and more recent genetic studies suggest that most of the population of Britain hasn't moved very far at all since prehistory), the ethnicity traits for the Casse as I understand them contradict what at least looks like the current majority view- every trait I've read so far gives an approximate century that the tribe concerned migrated from Gaul, and they are all 800BC and younger, so far as I've seen.

Of course I could be mistaken. Perhaps the idea of a series of immigrations from Gaul has made a comeback. Perhaps the invasion idea was retained because the game is Total War, and not Total Farming, so descriptions inclined toward the dramatic.
Do recall, the parts concerned - ie. the FMs etc. - are of the ruling/warrior class which so far as I've read did move around. And insofar as they're concerned "their tribe migrating here" means just that - since when did anyone really concern themselves with the common peasantry anyway ? It's not like the equivalent social strata in say Mesopotamia has really changed that much since the Sumerians either far as I know, but their overlords most certainly did.

As for the dates, well duh - the whole La Tene phase of Celtic culture and the accompanying diffusion of wandering warriors-of-fortune and cultural influences is younger than 800BC, AFAIK. Would be tricky indeed for the Celtic influences in the British Isles to be older than that.