Bonjour~!

French Republican Calendar Bot is a twitter bot I made that takes the current date, converts it to the French Republican Calendar, and then tweets it out for everyone to enjoy.

FRC Bot uses the Repubcal Python module by Nimlar, which in turn uses the ephem library.

This is mostly just a fun side project made for my own amusement and edification.

The technical details of the bot are not terribly interesting. It's a python script I wrote that runs the date conversion function from repubcal and then wraps it into a text string to tweet out. I also want to incorporate the rural calendar as well, in the future. But it currently doesn't do that.

As for the historical side, there's people out there who have written and done much better explanations about what the French Republican Calendar was and how it worked, but I'm going to briefly include a couple of basic points here to hopefully clear up some confusion.

First, it's not the "French Revolutionary Calendar" because it doesn't measure the days starting with the beginning of the French Revolution. It measures starting from 21 September, 1792, the date that the National Assembly abolished the Monarchy and declared France to be a Republic. Hence, Republican Calendar.

Second, the year starts on the Autumnal Equinox, because (by coincidence) the French Republic was declared on the Autumnal Equinox. So it starts on midnight of the Autumnal Equinox. Because of that, the Calendar handles leap years in an odd way. Originally the Calendar was defined as having a leap year every fourth year, but because the calculation used was based on astronomical events as measured from Paris. However, this meant that the actual number of years between a leap year would vary.

To fix this, a proposed solution by Gilbert Romme would substitute a mathematical rule basically identical to how the Leap Year is determined in the Gregorian system: every fourth year is a leap year, except century years not divisible by four. This proposal never entered legal force though, and various document and contracts written during the Republican period assumed that the years 3, 7, and 11 were leap years, which are inconsistent with Romme's method.

For that reason a different method of date leap year calculation is called Romme-1, where the leap day is inserted the year before years divisible by four, so that year 3,7,11 would stay leap years, consistent with the historically observed leap years. That's the method my bot uses to determine leap years, in case you were wondering.

Please DM me on twitter with questions, I'd love to tell you more about it.