| A Republican year consisted of 365 or 366 days, divided into 12 months of 30 days each, followed by 5 or 6 additional days. Those months were:
Each month was divided into three décades of 10 days, of which the final day was a day of rest - an attempt to de-Christianize the calendar; unsuccessful because it left a rest day only one in ten rather than one in seven. Even the lumpenproletariat (er... sans-culottes) get a whiff of something rotten when the work-week stretches to 150% what it used to be.
The ten days of each décade were named fairly straightforwardly Primidi, Duodi, Tridi, Quartidi, Quintidi, Sextidi, Septidi, Octidi, Nonidi, Decadi.
The 5 or 6 additional days following the last day of Fructidor went a little like this:
The Republican year was supposed to begin upon autumnal equinox (+- September 22nd) but since this isn't always the same problems arose from the woodwork as the years ticked by. (Not too many problems, mind you, on account of the calendar's only being in use for a period of fourteen years...)
And when did that period begin? Why, they counted starting from the establishment of the first French Republic on September 22nd, 1792, which went down in revised history as 1 Vendemiaire of the year 1 of the Republic. (Revised, mind you, since the Revolutionary Calendar was not introduced until November 24th 1793.)
And that's the rest of the story! | 
