In the aftermath of the French Revolution, such considerations were secondary to the zeal to throw off everything which reminded the citoyens of the yoke of monarchy and the church. Thus the Gregorian calendar was replaced by one which paid no allegiance to religion. It was designed by astronomers and mathematicians and was held up as a product of the new Age of Reason.
It harked back to the calendar of ancient Egypt. It had twelve equal months of thirty days, plus five or six festive days at the end of the year. Each month was divided into three ten-day weeks or decades.
The months were given names to reflect Nature and the changing seasons. They had a certain poetry.
| Order | Name | Gregorian dates¹ | Meaning of name | Origin of name |
|---|---|---|---|---|
| Autumn | ||||
| 1st | Vendémiaire | 22 Sept - 21 Oct | Grape harvest | Latin: vindemia |
| 2nd | Brumaire | 22 Oct - 20 Nov | Mist and fog | French: brume |
| 3rd | Frimaire | 21 Nov - 20 Dec | Wintry weather | French: frimas |
| Winter | ||||
| 4th | Nivôse | 21 Dec - 19 Jan | Snowy | Latin: nivosus |
| 5th | Pluviôse | 20 Jan - 18 Feb | Rainy | Latin: pluviosus |
| 6th | Ventôse | 19 Feb - 20 Mar² | Windy | Latin: ventosus |
| Spring | ||||
| 7th | Germinal | 21 Mar - 19 Apr | Germination | Latin: germen, germinis |
| 8th | Floréal | 20 Apr - 19 May | Flowering | Latin: floreus |
| 9th | Prairial | 20 May - 18 June | Meadow | French: prairie |
| Summer | ||||
| 10th | Messidor | 19 June - 18 July | Harvest | Latin: messis + Greek: dôron (gift) |
| 11th | Thermidor | 19 July - 17 Aug | Summer heat | Greek: thermon + dôron |
| 12th | Fructidor | 18 Aug - 16 Sept | Fruitfulness | Latin: fructus + Greek: dôron |
The five days at the end of the year were dedicated to the sans-culottes , the impoverished citizens who manned the barricades despite being under-dressed. The days were named after Virtue, Genius, Labour, Opinion and Recompense. In leap-years, the sixth day celebrated the French Republic itself.
The New Year was to begin on the date of the Autumn Equinox. The new calendar began on September 22nd, 1792.
The French Republican calendar faced several difficulties. The first, and greatest, was that nobody outside France recognised it, so that the French were forced to put two dates - one Republican, one Gregorian - on any letter or document that was to be sent outside France.
The second arose when the citoyens realised that in place of 52 days of rest each year, the new calendar gave them only 36.
The third was the rule which governed the New Year. To conform to truly scientific principles, and to reject all historical and religious precedents, it had been decided that New Year's Day each year should be the day on which the Autumn Equinox fell, on the meridian of Paris.
The problem is that the exact instant of the Equinox varies from year to year by up to 20 minutes either side of the mean instant that is predicted by the length of the tropical year. The variation arises from a combination of the nutation or ``nodding'' of the Earth's axis of rotation and the small deviations or perturbations of the position of the Earth in its orbit around the Sun due to the gravitational attraction of the other planet and the Moon.
In order to predict the amount by which the Equinox is slow or fast, astronomers can construct complicated mathematical formulae for the perturbations and the nutation with the aid of computers. In 18th-century France, such calculations had to be done by hand, and this was very laborious and time-consuming. It was not a good way to design a calendar.
In England, the Republican calendar met with derision. There was even a
parody of the names of the months:
| Autumn: | Wheezy, Sneezy, Freezy |
| Winter: | Slippy, Drippy, Nippy |
| Spring: | Showery, Bowery, Flowery |
| Summer: | Hoppy, Croppy, Poppy |
France's Republican Calendar, the calendar of the Age of Reason, survived almost thirteen years. In 1806, Napoleon Bonaparte ordered that France should return to the Gregorian calendar.