INTRODUCTION

In 1792, the French Revolution was in a dire situation. After months of instability, menaced by revolts in the country, and foreign armies attacking France from all sides, the Jacobins gave a coup and managed to take control of the Legislative Assembly. On 20th September 1792, the first assembly elected by universal male suffrage, the National Convention, held its first session. Monarchy was abolished and a deeply liberal Constitution was approved, although it never was implemented due to the constant situation of exception under the Jacobin government. Besides, the Jacobins committed themselves to totally remove everything deemed "old", "irrational", and "non-revolutionary".

It is understandable that under this situation, the calendar, something created by a Pope, with each day dedicated to one or several saints, and following irrational rules, with irregular months, seven-days weeks that weren't paired to the months... was soon considered something that had to be reformed. The Committee of Public Instruction formed a subcommittee, with mathematicians, astronomers and poets, to create a new calendar. The structure and rules of the calendar were defined by the politician Charles Gilbert Romme, with the poet Fabre d'Églantine inventing the names of the months.

The calendar consisted of 12 months of 30 days each, with 5 extra days (6 in a leap year) at the end to match the solar year. Instead of seven-days weeks, the months were divided on three ten-days weeks called décades. This decimal system established thus a much more regular and organized calendar.

The calendar was adopted of 24 October 1793, but the start of it was fixed on 22 september 1792, that was both the day the French Republic was proclaimed and that year's autumn equinox in Paris. Years were counted from 1792 and written in Roman numerals.

MONTHS

The twelve months were grouped by seasons (so, we have four groups of three months), and all the months in a group rhyme, probably an Eglantine's idea to make it easier to remember. The months were the following ones:

The last five days of the year, first named jours complémentaires' (complementary days), later sans-culottides (after the sans-culottes), and then again 'jours complémentaires', were national holidays:

And on leap years, the sixth day, La Fête de la Révolution, "Revolution Day"

DAYS

As we mentioned, each month had three décades. The days of each décade were given very obvious names:

Instead of saints, each day of the year was dedicated to a tool (days ending in 0), an animal (days ending in 5), or a plant or mineral (the rest).

I've taken these tables from Wikipedia, French Republican Calendar, and corrected some errors. (2007, February 11). In Wikipedia, The Free Encyclopedia. Retrieved 12:24, February 13, 2007, from http://en.wikipedia.org/w/index.php?title=French_Republican_Calendar&oldid=107414973

WRITING A DATE

A date was usually written like this:

24 Floréal CLXXXIV

(that's the day I was born, 14th May 1976 :) )

This day was dedicated to the valerian, a medicinal plant.

This calendar is so well organized that the name of the day and the décade would also give us the right date:

Quartidi, Décade 2, Flóreal CLXXXIV

But this was a much less usual way of writing dates.

A sans-culottide had been written like this

3 Sans-culottide CXXIX, Fête du Travail

LEAP YEARS

Leap years are a real problem in the French Revolution calendar. The rules said on one hand that 1 Vendémiaire (New Year's Day) had to be the day of the Autumn equinox observed from Paris. This made the years III, VII, XI and XV to be leap years. But the Edict that defined the calendar also said that leap years would follow the same rules of the Gregorian calendar (roughly speaking, a leap year each four years). This wouldn't have kept the calendar synchronized with the equinox.

There are different theories about how this problem was going to be solved. Some experts say that from year 20, it was going to follow the Gregorian rule: a year is a leap year if it can divided by 4, unless divisible by 100, unless divisible by 400. But as Project Pluto, one of the best sources I've found, say, a revolution so devoted to remove every influence of Christianity and so devoted to scientific principles, wouldn't have used a rule defined by a Pope, following no scientific principles.

Others say that this ambiguity about the leap year was left there with no solution, and so the equinoctal rule would have been used. But according to others, on year 20 a new rule would be used: a year is a leap year if it can be divided by 4, unless divisible by 128. This gives a simpler rule and a much better synchronization with the solar year.

THE END OF THE FRENCH REVOLUTION CALENDAR

The French Revolution calendar didn't die with the Jacobins, but it was clear it wouldn't last long. Not too many people got used to it, and trade fairs and markets kept using the Gregorian calendar. It's also been said that it made trade with other countries to be more complicated. And some argue that having a holiday each ten days instead of each Sunday made it impopular, but this is not true. Office, schools, shops and tribunals were required to close on quintidi afternoons, apart from the décadi. So, there was one and a half free days each 10 days, slightly better than a free day each seven-days week.

The calendar was first modified in 1802, after Napoleon signing the Concordat of 1801. And he finally abolished it on 1 January 1806. It was briefly used again during the 1848 revolution and during the Commune of 1871, to finally disappear in oblivion except for a few enthusiats who have recognized the great idea it was and its great advantages.

DECIMAL TIME

If the Jacobins took the pains of changing the calendar, of course they weren't going to keep untouched the so irregular traditional time. 24 hours a day, 60 minutes each, 60 seconds each? Instead of that, it was proposed an easier and more rational decimal time.

Each day was divided in 10 hours, so that the fifth hour was noon, and the tenth was midnight. Each hour had 100 decimal minutes, and each decimal minute 100 decimal seconds. Since there are 86400 "normal" seconds in a day, and 100000 decimal seconds, this gives the following equivalence:

1 decimal second = 0.864 seconds
1 decimal minute = 1 minute 26.4 seconds
1 decimal hour = 2 hours 24 minutes





If not everyone was an enthusiast of the Republican Calendar, the decimal time was received even much more coolly. Dual clocks and watches were built, showing conventional and decimal time, and there was some famous adherents like Laplace, who wrote the first two volumes of his Traité de Mécanique Céleste using decimal time units, apart from the decimal angle units that were also defined then. But decimal time was never really accepted, and so it was used only from 1 Vendémiaire III (22 September 1794) to 18 Germinal III (7 April 1795), six months and a half. Ironically, the only survivor of this "decimal fever", the metric system, was approved the same day decimal time was abandoned.

THE REPUBLICAN CALENDAR WIDGET

I've written a widget for Mac OS 10.4 (Tiger) that shows the Republican Calendar date (following the 4/128 rule for the leap years) and the decimal time. It is free software offered under the GPL. The images appearing on the widget were taken from the Republican Calendar of 1794 drawn by Louis-Philibert Debucourt, and they are on the public domain.

Using the 4/128 rule might not be the best choice from a historic point of view. But as it was explained before, since there are no clear rules, and this one is the most scientifically accurate and universal for our times, not depending on the equinox in Paris, nor in Gregorian rules, I think the 4/128 rule is a good choice.



Mac OS X 10.4 Tiger is required. If you're using Safari, click the download link. When the widget download is complete, Show Dashboard, click the Plus sign to display the Widget Bar and click the widget's icon in the Widget Bar to open it. If you're using a browser other than Safari, click the download link. When the widget download is complete, unarchive it and place it in /Library/Widgets/ in your home folder. Show Dashboard, click the Plus sign to display the Widget Bar and click the widget's icon in the Widget Bar to open it.

Last version of the software is 1.4. There is a slight correction on this version, plus the great corrections made in version 1.3 thanks to John Hynes's great help (http://decimaltime.hynes.net), who pointed me the so big, big errors in the older versions. So, please, if you're using older versions, update to this one at once!

And for those of you deprived of the pleasure of owning or using Mac OS X, or wanting a preview of the widget, just follow this link to open a new page and see the date and time.

I hope you enjoy it as much as much as I've enjoyed investigating this subject and writing the software. Feel free to offer suggestions, improvements and comments. Or better, since it's free software, write yourselves the improvements and let everyone enjoy them. :)

Download the Republican Calendar Widget

Download source code

José Luis Martín Mas

jlmartinmas "*-- --! gmail.com