Non-musical history for today: 1582 – With the papal bull Inter gravissimas, Pope Gregory XIII announced the Gregorian calendar. This replaced the Julian calendar in most of the world, although a few religions and other groups still use the Julian. I’m pretty sure I talked about this back in October on the anniversary of the Gregorian taking effect. The principal change was to space leap years slightly differently, making the average calendar year 365.2425 days rather than the Julian calendar’s 365.25 days, thus more closely approximating the 365.2422-day “tropical” or “solar” year determined by the Earth’s revolution around the Sun. The rule for leap years is that every year divisible by four is a leap year, except for years that are divisible by 100, except in turn for years also divisible by 400. For example, 1800 and 1900 were not leap years, but 1600 and 2000 were.
Music history, album anniversaries, birthdays, and deaths for February 24.