But if by "dehumanization" you really mean "racist," then yes indeed, slavery was originally based more on generic power imbalances (prisoners of war, or offspring of existing slaves) than any racial component. The racist aspect of slavery only became prominent with the emergence of colonialism and exposure of Europeans to "the new world." I'm not sure that race was even an attribute that the ancients felt worthy of mentioning - after all, Rome was an empire spanning many disparate races and cultures. Wikipedia [0] seems to agree ("skin tones did not carry any social implications"). I'd be curious to read more about it though.
[0] https://en.wikipedia.org/wiki/Black_people_in_ancient_Roman_...
> Wikipedia [0] seems to agree ("skin tones did not carry any social implications")
When I read this comment (before your edit), I was a bit surprised, since ethnicity and "blood/familial" relations were absolutely huge in ancient Rome.
I generally use a definition of race that's much broader than skin tone, and I see it as interchangeable with loosely defined ethnicity and cultural background.
(I guess you could argue that an empire that invaded another culture/nation/territory and then enslaved its people was effectively enslaving them based on something akin to "race," but that argument is slightly weakened by the fact that the Roman army didn't only conquer "barbarians" but also went to war against their contemporary civilizational peers, often driven by familial disputes between emperors.)
So while enslaving someone from birth is undoubtedly bad, I'm not sure it's fair to characterize it as enslavement based on racial attributes, if the slave's ancestor was originally enslaved for reasons unrelated to race. Like, I guess you could call it racism if you squint, but only in the sense that skin color (or whatever other physical attributes you might associate with race) is an inherited characteristic, which seems like self-referential reasoning.
e.g. the Romans kept slaves on a huge scale, but never bothered with a racist ideology to justify it. They just dehumanized almost anyone, their ethical system permitted blatant "might makes right." But the nominally Christian ethical system predominant in our most recent western society required a "reason" why slavery was permissible, and so we got the invention of race.
