To build on what Fatboy said:
While it was centuries before Rome was great, one could not be amiss to look at Herodotus' works, and how anyone not Greek was a 'barbarian' in his eyes. This represents something that suggests racial discrimination was more a matter of pride than hatred, because Herodotus even refers to the Persians as barbarians - they were in fact a very diverse culture with a number of impossible-to-ignore technological advances, not to mention the fact that they had thousands of men of Greek blood in their ranks.
Lawrence