French Republican New Year

The French republican calendar was based on a secular calendar first presented by Pierre-Sylvain Maréchal in 1788. French republican calendar, dating system that was adopted in 1793 during the French Revolution and which was intended to replace the Gregorian calendar with a more scientific and rational system that would avoid Christian associations. The Revolutionary Convention established the calendar on October 5, 1793, setting its beginning (1 Vendémiaire, year I) to a date nearly a year prior (September 22, 1792), when the National Convention had proclaimed France a republic.

The 12 months of the calendar each contained three décades (instead of weeks) of 10 days each; at the end of the year were grouped five (six in leap years) supplementary days. The months in order—beginning with one corresponding to the Gregorian months of September and October—were Vendémiaire (meaning “vintage”), Brumaire (“mist”), Frimaire (“frost”), Nivôse (“snow”), Pluviôse (“rain”), Ventôse (“wind”), Germinal (“seedtime”), Floréal (“blossom”), Prairial (“meadow”), Messidor (“harvest”), Thermidor (“heat”), and Fructidor (“fruits”). The names were the invention of poet Philippe Fabre d’Églantine. Each of the 360 days in the year was named for a seed, tree, flower, fruit, animal, or tool, replacing the saints’-day names and Christian festivals.

Source: britannica.com