Romme Leap Year Rule for French Republican Calendar

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Romme Leap Year Rule for French Republican Calendar

Karl Palmen

Dear Calendar People


Does anyone know the precise details of the Romme leap year rule for the French Republican Calendar? states that from year 20, leap years would have fallen on each year divisible by four (thus in 20, 24, 28…), except most century years, according to Romme's proposed fixed rules.


This would cause the FR new year to fall on the same Gregorian date until either calendar drops a leap day. So if the Romme rule is the same as the Gregorian rule, but for FR year numbers, then the new year days would fall as shown here:


017-100 September 23 1808-1891

101-108 September 22 1892-1899

109-200 September 23 1900-1991

201-300 September 22 1992-2091

301-308 September 21 2092-2099

309-408 September 22 2100-2199

409-500 September 23 2200-2291

and so on every 400 years


I think this is the only example of two leap year rules using the Gregorian leap year rule applied to different year numbering systems.


An alternative system referred to as continuous in the Wikipedia article has the leap years one year earlier to fit in with the actual leap years (3, 7, & 11). This has the leap day about a month and a half closer to the Gregorian leap day (Feb 29) than the Romme leap year rule. Hence it would have simple conversion to Gregorian for more dates than Romme, but not for the new year day.