I've seen recently a hypothesis brought forth on social media that the European idea of race and an associated caste system originated with the Crusades, and distinctions between Christians, Jews and Muslims. Is there scholarly work that backs this story?
[If you are in a rush and/or don't want to read everything, I always tend to try to make a conclusion section in my answers to have the mains points (without the stories and explanation though), so if you want a quick answer, go see that section, otherwise enjoy the reading :) ]
Hello,
So your question really made me raised my eyebrows since I've never heard of the concept of "race" being a thing before the colonization (mostly from the European colonization of Africa where the autochthones were more present in number compare to the Americas). I did some research online to counter my point, but I found "nothing." To help you, I'm going to go over the Etymology side of the key-word "race," then the biological standpoint and the History of race.
Etymology :
First thing, I feel it's important to define the word itself, or at least its concept. I have a huge problem to understand the whole issue in the USA when I moved there for the simple reason is that in English the word "race" as a false meaning. The word "race" (and not as in "racing cars" of course, totally different and not the same roots) itself is from the French word "race" (and I'm French, I'll come back to that later) which seems to come from the Italian word "razza," and both are originating from the XVI century (without knowing its history before that).
In French, the word "race" could be translated into "breed" into English, and for me, that's part of the problem on its use in English language (especially in North America). While the English word "race" would be translated in French into "ethnicité" (ethnicity).
Biology :
The problem with that word is that "race" is suppose to mean "breed," and technically, it's been quite a while since other races of Human beside Homo Sapiens has been around (between 30 and 50 000 years). You, me, your neighbor, are all part of the Species of "Homo." A race is just a type of karyotype's expression within a species. For example, a puddle is a race of dog, such is an English bulldog.
In order to facilitate organization of all living things we categorize them into different groups, so for example we are from the Animalia Kingdom, Chordata Phylum (...) Homini Tribe, Homo Genus, and Homo Sapiens Species (what we vulgarize into "race").
History :
Before racism (in the sense of the study and classification of the different ethnicity of the Humans), you didn't have a real or common idea of race. As Jean Gayon and Christian Delacampagne (my main sources) explain in theirs books "Le corps racialisé. Le philosophe et la notion de race" and "Une histoire du racisme," the notion of racism is based on a "natural aspect rather than a societal aspect," which explain the reason of the appearance of the word in the XV-XVI century and not before where such science weren't that common.
However, Humans were style categorized within different groups. Jews were the center of that notion (since they always been tolerated and used around Medieval Europe and even before without being fought as the Muslim have been, but that's another subject). The idea of different category really had an impact and got real bases starting 1449 in the Iberia Peninsula, where "a system of blood purity (limpieza de sangre) in order to access certain corporation or to be accepted in universities and orders" is set up. You find that in the Alhambra Decree of 1492 where 4 mains groups are described : the Jews, the converted Muslim, the Inquisition's penitentiaries and the lepers' descendants. For Delacampagne, this decree is the premise of "modern racism" where the categorization of people (especially the lepers) is not based anymore on a social construct but on and through a scientific method.
In conclusion :
It's important to know what you're looking for, are you looking for "race" as "modern racism" (idea that different ethnicity of humans are ranked) or if you are looking for "race" as just a categorization of ethnic and cultural group. According your word and sense choice, you'd look at very very different type of scholar studies and ideas.
I'm not sure that I'm really answering your question in the end, I feel like I'm more giving you tips and way to narrow down your research, or that I killed the idea in its egg.
However, from what I gathered, J.Gayon and C.Delacampagne seem to have done a good job in the research of History of Racism (with another interesting book " Corps normalisé, corps stigmatisé, corps racialisé").
Thus my final answer to your question would be : there is no scholar source to support the idea that the crusades created any idea of "race" in the North American/English meaning within the European, it seems like it would be a little too early.
If you want, I can make some research on the idea of the different "kingdoms" (Christendom was seen as a "kingdom" in some ways with its own way of life that made Crusades possible, same thing with the Muslim world and the Djiad, the Jews is more complicated but extremely interesting and would most likely make you realize that the genocide isn't a real surprise when you see the build up of animosity against the Jews throughout History). Or you can try to look into it, that might answer your question. Look especially the History of the Middle East, it's a gold mine for that kind of things since the 3 monotheists religions have a history of cohabitation over there for centuries.