Not to discourage other answers, but you might be interested in these posts about race in Rome while you're waiting for an answer here:

• How would I be treated in Ancient Roman as a black man? - /u/Tiako

• I know the Romans had no conception of race, but did they view Black Africans any differently than they did the Persians, Libyans, or Celts? - /u/thelastoneusaw

• How true is the statement "Race is a modern idea. Ancient societies, like the Greeks, did not divide people according to physical distinctions, but according to religion, status, class, even language"? - /u/medieval_pants

• Monday Methods: "No but what race were the ancient Egyptians really?" – Race as a concept in history - /u/commiespaceinvader and others

The first 2 posts I listed are a bit old, but the third post and the Monday Methods post is are more recent, and excellent reads.