An insane bunch of French Protestants in the 17th century (about the time of the 3 Musketeers). Had they not been wiped out almost to a one on St. Bartholomew's Day, they would have introduced the same sort of insanity to France as the Scots Planters inflicted upon Ireland. While most were exterminated, some fled to Blighty, and changed the spellings of their names to seem British (ie: Gerrow = Giroux). Largely forgettable.
Perfectly reasonable bunch of christians who wanted to sing their psalms in French rather than Latin. At their height numbered 2 million in a French population of 18 million. Oppressed and murdered by a catholic nation hell bent on ensuring that the schism in christianity (caused by corruption in the catholic faith) was wiped out.
In the St. Bartholomew's Day Massacre of 24th August till 17th September 1572, Catholics killed thousands of Huguenots in Paris. If you add in the surrounding villages and depending who's side you listen to, as few as 5 000 or as many as 110 000 protestants were murdered in cold blood by the catholic mob. The true numbers are not known.
Good example of Religious Wars and one of the few wars that France was guaranteed a win no matter which side won.