Okay, well maybe I don't REALLY know but I do have a theory as to why the Romans (especially Caesar) were so determined to destroy the druids.

While many folks have adopted the view of them is that of priests, the truth appears they had the tripartite duties of priests, philosophers and judges. The ancient world didn't have the separation of church and state that we do now. Instead of being a mysterious magician priests, they actually were an oligarchical elite with both judicial and religious duties.

So, looking at this from this perspective, it appears that Caesar has a much clearer picture of the druids than many have given him credit for. He understood the importance of the druids to the Celts. By removing them, it was a given that within a generation or two, much of what had made them Celts vanished.

Brynna, the Romans thought everyone who was not Roman or Greek were barbarians. It didn't matter to them how intelligent or how advanced their civilization was - they were different, so they were barbarians.