[Janet MacD]

If you are trying to trace postal history on covers from France or areas ruled by France sent between 1793 and 1805, the dates may not make sense. Instead of the Gregorian calendar, France created a new calendar that was stripped of religious references. 

You can read about it under the Wikipedia heading “French Republican calendar”. The following link will take you to a nifty site with a conversion tool:

https://www.napoleon-empire.org/en/repub...lendar.php

If you were born in early April, like me, you are a child of Germinal, a name that evokes sap.

This was an idea that didn’t last …

[Hugh]

Thanks, a very nice digital tool for date conversion. 

Here's one of my départements conquis covers with an old-style date from after the revolution. It was mailed from  'Charleroy' (now Charleroi) to Mons on 7 Messidor Year X. Now in Belgium, both towns were then under French occupation and had been since 1794. Mons was the principal city of the new département 86 - lands taken from the Austrian Netherlands. 

There is a black ink hand-stamp P86P / CHARLEROY. The P86P means the post was pre-paid. This is also confirmed by the manuscript Franco in the upper right hand corner. In 1802 the rate for letters under 6g going less than 100km would have been 2 décimes.

Image 31.jpeg Size: 105.86 KB  Downloads: 12

It was addressed: 
Au Citoyen
Dellainne, Directeur de
la Regie général d'affaires
rue des dominicains No. 30
à Mons

That is, To Citizen Dellainne, Director of General Admistration Policy, Number 30, Street of the Dominicans, in Mons.

The date was written at the top of the letter,  7 Messidor Year X:

   

Using the date converter we see that this is June 26, 1802. Cool.