I didn't know that cultures deal with portraits.
To stereotype ancient cultures based on modern popular cultures....
I would assume that Celts would be characterized though long red/blonde hair?
Nomads with long hair and several tattoos?
Greeks with togas and Corinthian helmets?
Arabians with darker skin complexion?
Romans - in classic EB1 attire.
Persians with darker hair, covered with jewelry
etc...
Um, is there going to be African negroes represented? I don't think they were too important in the development of Europe during this time, so to avoid having to make portraits for them I would contract the current map to the borders of Numidia and the northern Nile

I can't wait to see how EB will represent cultures!