By accident I came across this article in Jstor about the Cagots, the forgotten untouchables of France. They suffered discrimination for many centuries, but no one knows seems to know why although there are many theories. They were erased as a group from France through assimilation, even though up until the beginning of the 20th century it was shameful for a non-Cagot person to marry a Cagot. You can still see evidence of the discrimination they felt in churches in France, where the Cagots had a separate entrance and separate fonts.
All in all, a fascinating story of a mysterious people. I find them especially fascinating because of how they show a group can suffer discrimination and persecution, even though there is nothing different about them, other than the fact they can be labelled and considered worthy of such poor treatment.
For more on the Cagots, see wikipedia. For a story on someone who claimed Cagot ancestry, see this.
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