Tried asking this on the Reddit history pages, immediately removed for asking for a "basic fact", meanwhile sourcing is near impossible to find.
Ive been trying to find more sources on the origins of the racial identity construct, particularly in the development of widespread white supremacy, and how the "white" identity developed. In my research, it has seemed very clear that it developed in conjunction with the Catholic Church's rise to power at the continental scale. In this same location, fertile birthing grounds for settler-colonialism, capitalism, and white supremacy. Any recommended reading on the subject would be greatly appreciated.
Furthermore, as the title stated, I am looking for the earliest recorded instances of one peoples inflicting subhumanization behavior on another. Obviously conflict between different groups of people traces far back before recorded history, but I am very interested in finding when a group first identified as "pure" human, while declaring all those without said traits subhuman. I have a feeling there must be some Marxist text on this, so if anyone knows it I'd love to see it.
Selfish plug to the research I've done thus far if anyone wants to check it out
Modern whiteness maybe, but that had to originate somewhere. I've been looking into the crusades and how they managed to recruit an army from various European peoples with lots of language that seemed to signify a collective white christian identity, though to what degree "white" had anything to do with it is still something I need to do more research on.
You are right of course, just wanted to chime in on this point because you mentioned white identity specifically in the post. I think White Identity is a "modern" Anglicized expression of the otherizing phenomena you are talking about.