The Ancient identity system was more about language. Romans saw Celts as barbarians, for example, even though they were both European and had the same phenotype. I know the modern terms and understanding of race comes from the Colonial era, but why did it shift? And what caused this? Any works written on this subject would be much appreciated!
Hi there -- you may be interested in this recent answer from u/sowser, in which they go into some detail about how race is constructed through the experience of the Transatlantic slave trade. The whole thing is worth a read, but constructions of race are in part 4.