The French Republican calendar (French: calendrier républicain français), also commonly called the French Revolutionary calendar (calendrier révolutionnaire français), was a calendar created and implemented during the French Revolution and used by the French government for about 12 years from late 1793 to 1805, and for 18 days by the Paris Commune in 1871, meant to replace the Gregorian calendar.
The calendar consisted of twelve 30-day months, each divided into three 10-day cycles similar to weeks, plus five or six intercalary days at the end to fill out the balance of a solar year. It was designed in part to remove all religious and royalist influences from the calendar, and it was part of a larger attempt at dechristianisation and decimalisation in France (which also included decimal time of day, decimalisation of currency, and metrication). It was used in government records in France and other areas under French rule, including Belgium, Luxembourg, and parts of the Netherlands, Germany, Switzerland, Malta, and Italy.
The National Constituent Assembly at first intended to create a new calendar marking the "era of Liberty", beginning on 14 July 1789, the date of the storming of the Bastille. However, on 2 January 1792 its successor the Legislative Assembly decided that Year IV of Liberty had begun the day before. Year II had therefore begun on 1 January 1790.
On 21 September 1792 the French First Republic was proclaimed, and the new National Convention decided that 1792 was to be known as Year I of the French Republic. It decreed on 2 January 1793 that Year II of the Republic had begun the day before. However, the new calendar as adopted by the Convention in October 1793 made 22 September 1792 the first day of Year I. The Common Era, commemorating the birth of Jesus Christ, was abolished and replaced with l'ère républicaine, the Republican Era, signifying the "age of reason" overcoming superstition, as part of the campaign of dechristianisation.
The calendar is frequently named the "French Revolutionary Calendar" because it was created during the revolution, but this is a slight misnomer. In France, it is known as the calendrier républicain as well as the calendrier révolutionnaire. There was initially a debate as to whether the calendar should celebrate the revolution, which began in July 1789, or the Republic, which was established in 1792. Immediately following 14 July 1789, papers and pamphlets started calling 1789 year I of Liberty and the following years II and III. It was in 1792, with the practical problem of dating financial transactions, that the legislative assembly was confronted with the problem of the calendar. Originally, the choice of epoch was either 1 January 1789 or 14 July 1789.
After some hesitation the assembly decided on 2 January 1792 that all official documents would use the "era of Liberty" and that the year IV of Liberty started on 1 January 1792. This usage was modified on 22 September 1792 when the Republic was proclaimed and the Convention decided that all public documents would be dated Year I of the French Republic. The decree of 2 January 1793 stipulated that the year II of the Republic began on 1 January 1793; this was revoked with the introduction of the calendar, which set 22 September 1793 as the beginning of year II. The establishment of the Republic was used as the epochal date for the calendar; therefore, the calendar commemorates the Republic, and not the Revolution.
The Concordat of 1801 re-established the Roman Catholic Church as an official institution in France, although not as the state religion of France. The concordat took effect from Easter Sunday, 28 Germinal, Year X (18 April 1802); it restored the names of the days of the week to the ones from the Gregorian calendar, and fixed Sunday as the official day of rest and religious celebration. However, the other attributes of the republican calendar, the months, and years, remained as they were.
The First Republic ended with the coronation of Napoleon I as emperor on 11 Frimaire, Year XIII, or 2 December 1804. Despite this, the republican calendar continued to be used until 1 January 1806, when Napoleon declared it abolished. It was used again briefly in the Journal officiel for some dates during a short period of the Paris Commune, 6–23 May 1871 (16 Floréal – 3 Prairial Year LXXIX).
The prominent atheist essayist and philosopher Sylvain Maréchal published the first edition of his Almanach des Honnêtes-gens (Almanac of Honest People) in 1788. The first month in the almanac is "Mars, ou Princeps" (March, or First), the last month is "Février, ou Duodécembre" (February, or Twelfth). The lengths of the months are the same as those in the Gregorian calendar; however, the 10th, 20th, and 30th days are singled out of each month as the end of a décade (group of ten days). Individual days were assigned, instead of to the traditional saints, to people noteworthy for mostly secular achievements. Later editions of the almanac would switch to the Republican Calendar.
The days of the French Revolution and First French Republic saw many efforts to sweep away various trappings of the ancien régime (the old feudal monarchy); some of these were more successful than others. The new Republican government sought to institute, among other reforms, a new social and legal system, a new system of weights and measures (which became the metric system), and a new calendar.
Amid nostalgia for the ancient Roman Republic, the theories of the Age of Enlightenment were at their peak, and the devisers of the new systems looked to nature for their inspiration. Natural constants, multiples of ten, and Latin as well as Ancient Greek derivations formed the fundamental blocks from which the systems were built.
The calendar was created by a commission under the direction of the politician Gilbert Romme seconded by Claude Joseph Ferry and Charles-François Dupuis. They associated with their work chemist Louis-Bernard Guyton de Morveau, mathematician and astronomer Joseph-Louis Lagrange, astronomer Jérôme Lalande, mathematician Gaspard Monge, astronomer and naval geographer Alexandre Guy Pingré, and poet, actor and playwright Fabre d'Églantine (who invented the names of the months) with the help of André Thouin (gardener at the Jardin des plantes of the Muséum National d'Histoire Naturelle in Paris). As the rapporteur of the commission, Romme presented the calendar to the Jacobin-controlled National Convention on 23 September 1793, which adopted it on 24 October 1793 and also extended it proleptically to its epoch of 22 September 1792. It is because of his position as rapporteur of the commission that the creation of the republican calendar is attributed to Romme.
French coins of the period used the calendar. Many show the year (French: an) in Arabic numerals, although Roman numerals were used on some issues. Year 11 coins typically have a "XI" date to avoid confusion with the Roman "II".
Years usually appear in writing as Roman numerals. Roman numeral I indicates the first year of the republic, that is, the year before the calendar actually came into use. By law, the beginning of each year was set at midnight, beginning on the day the apparent autumnal equinox falls at the Paris Observatory.
There were twelve months, each divided into three 10-day weeks called décades. The tenth day, décadi, replaced Sunday as the day of rest and festivity. The five or six extra days needed to approximate the solar or tropical year were placed after the final month of each year and called complementary days. This arrangement was an almost exact copy of the calendar used by the Ancient Egyptians, though in their case the year did not begin and end on the autumnal equinox.
A period of four years ending on a leap day was to be called a "Franciade". The name "Olympique" was originally proposed but changed to Franciade to commemorate the fact that it had taken the revolution four years to establish a republican government in France. The leap year was called Sextile, an allusion to the "bissextile" leap years of the Julian and Gregorian calendars, because it contained a sixth complementary day.