The year 1700 was a leap year by the Julian calendar but not by the Gregorian, and therefore March 1, 1700, Julian, corresponded to March 12, 1700, Gregorian, the difference then amounting to ...

Thursday (Feb. 29) is "leap day," an artifact that dates back to the year 46 B.C. Find out how this calendar oddity came to be.

In the Julian calendar, the new year began on March 25. So March 24, 1701 would be followed directly by March 25, 1702. The Gregorian calendar, as we know today, begins on January 1. ...

This brought the average length of the Gregorian year to 365.2425 days, off by just 26 seconds compared to a solar year. While under the Julian calendar, a day shift accumulated every 129 years ...