I've read that the 1912 Russian Olympic team showed up two weeks late because they were using the wrong calendar, the old one, that kept getting further and further off of the seasons.
This is due to the switch from the Julian Calendar to the Gregorian Calendar.
The principal change was that leap years were reduced from every fourth year to . . . not quite every fourth year as defined below:
- Every year evenly divisible by four is a leap year except that
- Years that are also evenly divisible by 100 are not leap years except that
- Years that are evenly divisible by 400 ARE leap years.
Thus:
- 1896 WAS a leap year (divisible by 4)
- 1900 was NOT a leap year (divisible by 4 but also divisible by 100)
- 2000 WAS a leap year (divisible by 400).
When the Romans made the Julian Calendar they approximated a year as 365.25 days so they made a 365 day year and added a leap year every fourth year. It actually takes the earth 365.2422 days to revolve around the sun so one leap year every four years is a little too much.
The problem it caused was that the timing of various festivals and religious holidays was slowly creeping seasonally. The old (Julian) calendar was off by approximately one day every century. The new (Gregorian) calendar is still not QUITE exact but it is only off by one day approximately every 7,700 years.
Interesting trivia about adoption:
The Gregorian Calendar is so named in honor of Pope Gregory who was Pontiff in Rome when it was first adopted in 1582. However, adoption took many centuries. England and the Nordic countries were some of the last in Europe to adopt it for the rather obvious reason that they were NOT Catholic and therefore wanted nothing to do with a Catholic calendar named for a Pope. Thus it wasn't adopted in England (and also British Colonial America) until 1752. Consequently, if you google George Washington you will find that he was born on either February 11, 1731 or February 22, 1732. When he was born it was recorded as occurring on February 11, 1731 but the English adoption of the new calendar (they didn't and still don't officially call it the 'Gregorian Calendar') they moved the start of the year from March 25 to January 1 and lopped fast-forwarded 11 days.
Interesting (to me anyway) trivia question:
What happened in France on the dates from December 10, 1582 through December 19, 1582 inclusive?
Answer:
Absolutely nothing. Nobody was born, nobody died, there were no wars, there weren't even any strikes or riots. When they adopted the Gregorian Calendar they had to advance so December 9 was followed immediately by December 20.
