There is a mediæval Welsh story, The Story of Lludd and Llefelys, written down in 12th or 13th century, usually published alongside the Mabinogion. The story describes the counsel taken by Lludd, ruler of Britain, with his brother Llefelys, ruler of France, regarding three terrible plagues that afflict the former's kingdom.
The first of the plagues (and the only one I'm going to talk about) is described very briefly. This plague consists of a people called the Coraniaid who have moved into Britain, and they apparently can hear anything that the wind hears, so it is impossible to plot against them (that's all we are told about how horrible they are).
It takes a little work for the brothers to discuss things; they have to use a brass horn to talk through so the wind (and thus the Coraniaid) won't hear them, and they need to wash a demon out of it with wine. Anyway, Llefelys gives Lludd some insects in order to deal with the Coraniaid. He's to set some of them aside for breeding (in case the Coraniaid ever come back), and mash up the rest in water. Then call a big meeting of the Britons and the Coroniaid together, with the pretense of making peace between them, and sprinkle the water over the whole crowd. The insect-water will utterly destroy the Coraniaid, but won't harm the Britons at all.
OK, am I the only one who finds this to be xenophobic almost to the point of offensiveness? Nobody else seems to have noticed this. These Coraniaid are described as a plague, and what horrible suffering do they inflict? Apparently just being there and being impossible to be mean to. And for this, our heroes are determined to lie to them, and trick them under false pretenses of peace, in order to exterminate them. I guess it's sort of okay, since the fact that they're susceptible to these insects while decent, red-blooded Britons aren't shows that they're not completely human, right?
This sounds a lot like the basest of accusations leveled against various (immigrant) ethnic groups through the ages (especially against Jews, actually). “Gee, something has to be done about these horrible people. Well, no, they're not actually doing anything wrong, but they're too clever/hardworking/cunning/sharp-eared to compete with. And they're taking up space/land/services/jobs that should be going to real Britons/Americans/locals.”
It just sort of struck me how blatant the bigotry was in this case. I guess it makes a certain amount of sense in the small, local world back then. People are bad simply by virtue of not being locals, and when they move in they're invaders, and any means are valid to repel them.