In a long passage to show that different nations have different customs, and what one considers natural is an abomination to another, Jerome talks about cannibalism among barbarians, weird foods people eat, and so on. Then he says,
The Persians, Medes, Indians, and Ethiopians, peoples on a par with Rome itself, have intercourse with mothers and grandmothers, with daughters and granddaughters. [Against Jovinianus, Book II, 7.]
This is pretty good evidence for my thesis that ancient Romans generally weren’t racists. They could find all sorts of reasons to hate you, but it seems not to have occurred to them that skin color was one of them. Ethiopia was a civilized nation, like Rome or Persia. It had wicked customs, but Jerome would be the first to admit that pagan Romans, and probably even most of the Christian Romans, weren’t any better.