History is messy. European history no less so. Even, or especially, in what could be called ancient times or antiquity. Groups that have now been considered the norm for centuries or millennia might be considered invaders, or ripe for plucking. At turns dismissed, vilified, and romanticized. A pattern that would be repeated elsewhere in the world.
Reading and looking at the museum exhibit companion Ancient Gold: The Wealth of the Thracians shows an example. The Thracians lived in Eastern Europe, their turf overlapping with much of modern day Bulgaria. Herodotus characterized them as single-minded cruel warriors. There was probably some measure of propaganda to this, although they do seem to have been a martial society. A belief in divine right of kings is still ascribed to them.
On the romantic side, the tragic mythical musician and poet Orpheus is said to have been from Thrace. Possibly tied into this is evidence of shamanic ritual.
Difficulty in saying anything more definitive results from the fact that there's very little written record from their societies. The Thracians didn't have their own alphabet, or at least none that was widely known. The few fragments of their language that have survived are in the Greek alphabet. Eventually the Greek language itself took over.
This was the time in history when Greece and Rome were ascendant. That's a good thing in a lot of ways. Their legacy includes equality before the law and at least some form of democracy. It's a shame some peoples were destined to be forgotten, though.