page_title: French Republican calendar
section_title: Criticism and shortcomings
hierarchical_section_title: French Republican calendar / Criticism and shortcomings
context_page_description: The French Republican calendar, also commonly called the French Revolutionary calendar, 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. The revolutionary system was designed in part to remove all religious and royalist influences from the calendar, and was part of a larger attempt at decimalisation in France. 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.
context_section_description: Leap years in the calendar are a point of great dispute, due to the contradicting statements in the establishing decree stating:
  Each year begins at midnight, with the day on which the true autumnal equinox falls for the Paris Observatory.
  and:
  The four-year period, after which the addition of a day is usually necessary, is called the Franciade in memory of the revolution which, after four years of effort, led France to republican government. The fourth year of the Franciade is called Sextile.
  These two specifications are incompatible, as leap years defined by the autumnal equinox in Paris do not recur on a regular four-year schedule. Thus, the years III, VII, and XI were observed as leap years, and the years XV and XX were also planned as such, even though they were five years apart.
  A fixed arithmetic rule for determining leap years was proposed in the name of the Committee of Public Education by Gilbert Romme on 19 Floréal An III (8 May 1795). The proposed rule was to determine leap years by applying the rules of the Gregorian calendar to the years of the French Republic (years IV, VIII, XII, etc. were to be leap years) except that year 4000 (the last year of ten 400-year periods) should be a common year instead of a leap year. Shortly thereafter, he was sentenced to the guillotine, and his proposal was never adopted and the original astronomical rule continued, which excluded any other fixed arithmetic rule. The proposal was intended to avoid uncertain future leap years caused by the inaccurate astronomical knowledge of the 1790s (even today, this statement is still valid due to the uncertainty in ΔT). In particular, the committee noted that the autumnal equinox of year 144 was predicted to occur at 11:59:40 pm local apparent time in Paris, which was closer to midnight than its inherent 3 to 4 minute uncertainty.
  The calendar was abolished by an act dated 22 Fructidor an XIII (9 September 1805) and signed by Napoleon, which referred to a report by Michel-Louis-Étienne Regnaud de Saint-Jean d'Angély and Jean Joseph Mounier, listing two fundamental flaws.
  The rule for leap years depended upon the uneven course of the sun, rather than fixed intervals, so that one must consult astronomers to determine when each year started, especially when the equinox happened close to midnight, as the exact moment could not be predicted with certainty.
  Both the era and the beginning of the year were chosen to commemorate an historical event which occurred on the first day of autumn in France, whereas the other European nations began the year near the beginning of winter or spring, thus being impediments to the calendar's adoption in Europe and America, and even a part of the French nation, where the Gregorian calendar continued to be used, as it was required for religious purposes.
  The report also noted that the 10-day décade was unpopular and had already been suppressed three years earlier in favor of the 7-day week, removing what was considered by some as one of the calendar's main benefits. The 10-day décade was unpopular with laborers because they received only one full day of rest out of ten, instead of one in seven, although they also got a half-day off on the fifth day. It also, by design, conflicted with Sunday religious observances.
  Another criticism of the calendar was that despite the poetic names of its months, they are tied to the climate and agriculture of metropolitan France and therefore not applicable to France's overseas territories.
caption: Clock dial displaying both decimal (inside the circle) and duodecimal time (on the outer rim)
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