The bow tie originated among Croatian mercenaries during the Prussian war of the 17th century: the Croat mercenaries used a scarf around the neck to hold together the opening of their shirts. This was soon adopted (under the name cravat, derived from the French for "Croat") by the upper classes in France, then a leader in fashion, and flourished in the 18th and 19th centuries. It is uncertain whether the cravat then evolved into the bow tie and four-in-hand necktie, or whether the cravat gave rise to the bow tie, which in turn led to the four-in-hand necktie.