Application de l’analyse à la géométrie, par G.Joseph-Louis Lagrange, comte de l’EmpireĪ special thanks to Kevin Moore for creating this exhibit.Calendar reform since the mid-18th century, Britannica Academic.Historical information about the calendar came from the following: Leap days could be added as one more festival day, signifying the end of another four-year period know as Franciade. The final five days of each 365-day year were set aside for vacations and festivals before the autumnal equinox. Every month consisted of three, 10-day décades instead of weeks. The mathematicians’ final design consisted of 12 months of 30 days each. Joseph-Louis Lagrange (seminal figure in number theory and analytic and celestial mechanics) and Gaspard Monge (inventor of descriptive geometry) collaborated to create the new system. When it came to the technical design of the French Republican calendar, the National Committee enlisted the help of two prominent mathematicians. Transposing dates between the French Republican calendar and the Gregorian calendar complicated communications with other countries and France formally switched back to the Gregorian calendar on January 1, 1806. The calendar was implemented on Octoand received and official, backdated starting day of 1 Vendémiaire, year I (Septemaccording to the Gregorian calendar).įrance soon became disenchanted with its new calendar through. All 12 months received new names and the beginning and ending days of each month were changed to better align with the various equinoxes and the changing seasons. The design drew inspiration from a similar calendar proposed by French poet and playwright Pierre-Sylvain Maréchal in 1788. The result was the French Republican calendar. By Tresca, Salvatore (Graveur) – Lafitte, Louis (Dessinateur du modèle)ĭuring the height of the French Revolution in 1793, France’s National Convention set out to replace the widely used Gregorian calendar with a new version divorced from any Christian associations and instead grounded in logic and reason.

French revolutionary calendar