[FX.php List] [OFF] Interesting history date()

[Troy Meyers]

Forgive me if this is list pollution, but with the discussion of Feb. 28 and how the devil is in the details, from a historical and a programming standpoint I found this interesting.

My friend Brian Gorman frequently writes a little piece about "what happened today in history" and this is what he had to say today, Feb. 24th.....

-Troy


On this day in 1582, Pope Gregory XIII issued a Bull ("Inter gravissimus") that to this day drives our civilian lives. It established what we call the Gregorian calendar, doing away with the Julian calendar (after Julius Caesar) and aligning the solar year, with its important agricultural aspects of spring planting, for example, with the civil year, which had gotten badly out of whack with what was going on in the heavens and with the seasons.


Because the time it takes for the Earth to make a complete circuit around the Sun is so very odd (365 days, 5 hours, 49 minutes and 12 seconds) any regular calendar that can't adjust for the partial day at the end of the year is bound to cause problems that accumulate over time. The Julian calendar did try to adjust, with a leap year every four years. But that adjustment is just a tad off, since a quarter of a day is six hours exactly and by 1582 the Julian civil calendar, spring (March 21) was arriving about 11 days late.


The new calendar, kept the old Julian notion of leap year every four years, but added a caveat: no year exactly divisible by 100 is a leap year unless it is also exactly divisible by 400. So, in the last millennium, 1600 and 2000 were leap years, but 1700, 1800 and 1900 were not. In this millennium, 2100, 2200, 2300 and 2500 will not be leap years, but 2400 will be. But you probably won't be around to notice.


There was some odd fallout from the new calendar. It was initially adopted only by Catholic countries (Spain, Portugal, Italy, for example), where, to make up for the days that had been erroneously added from Roman times Thursday Oct. 4, 1582 was followed by Friday Oct. 15.  Protestant countries like Holland, Germany and most of eastern Europe eventually adopted the new calendar. Firmly Reformation-minded Britain (remember who was on the throne in 1582!) finally embraced the Gregorian calendar in 1752, when Wednesday, Sept. 2 was followed by Thursday, Sept 14.


Oh, that funny name for the Bull? It means "Among the most serious," and is the beginning of the document's fuller title of "Among the most serious of our pastoral duties...."