While experts prepare more targeted answers, here are some threads with background information on the topic from the FAQ section on “Racism and Slavery":
Race and Slavery in Antiquity
"I don't think that ancient slavery is really comparable to the chattel slavery that we saw in the Americas." How did ancient slavery differ from the atlantic slave trade? - 91 comments, over 6 months old.
This thread is mostly about Roman slavery including how slaves were acquired, what they were used for, and what ethnicity/race they were and thus allowing comparison with the situations presented in the threads above.
" it should be noted that slavery in the ancient Roman Empire was closer to the modern-day employer-employee relationship, not the slavery of other eras based on kidnapping and racism" some biblical scholar - 47 comments, over 2 years old.
Specialists on both eras involved engage in comparisons and debate on ancient and early modern slavery.
I've often heard it said that the ancient Romans were so culturally and ethnically non-homogenous that "racism" as we now understand it did not exist for them. Is this really true? - 137 comments, over 2 years old.
This thread dives headlong into the matter, inciting debates over whether the ethnic stereotypes common in the ancient world are of the same kind as modern racism or not while supplying plentiful evidence and analysis for both sides.
Was there much racism in the Roman Empire directed at people from other regions? - 47 comments, over 1 year old.
The commenters in this thread differentiate between the xenophobia present the ancient world from the modern understanding of racism.
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? - 80 comments, over 11 months old.
This thread goes into the way Rome interacted with peoples that would be classified in the modern day as being of different races.
Related Threads
do historians mean something different then normal people when they use the word "racism"? - 11 comments, over 2 years old.
Commenters here talk about concepts of race as dealt with in Anthropology and other related fields.
Racism in the ancient world? - 37 comments, over 1 year old.
This thread pulls examples from all across the world and its history along with copious amounts of sources for further reading.
Did the Romans have stereotypes about the behavior of people from particular tribes or geographic areas? - 9 comments, over 11 months old.
Several commenters detail the most common stereotypes that Romans held of others at the borders of their empire and beyond.