Right, Sorcha. In 1752 (?) in England they simply dropped 10 or 11 days from the calendar during the month of October. (Anybody know the details for sure?) Different places around the world did the same eventually. I think that Russia actually waited until around 1900 sometime.

And the reason did indeed have to do with astronomy. The Vernal Equinox had moved 10 days or so from March 21 because the length of a year is not exactly 365 days. Today we fix it with Leap Days.

BB,
NightWing