| This Leap Day arises from the esoteric, three-step rule
governing when a 29th day is added to February to mesh with the cycle of seasons. The rule took effect with the calendar introduced by Pope Gregory 13 in 1582.
It says the extra day is added in years evenly divisible by 4 except when the year is
divisible by 100 -- unless the year is divisible by 400.
Thus 2000 is the first Leap Year of its kind since 1600. The years
1700, 1800 and 1900 were not Leap Years. The 400-year exclusionary rule was to fix the
growing lag between the spring equinox and the date under the old Julian calendar,
introduced by Julius Caesar in 46 B.C., according to the U.S. Naval Observatory, the U.S.
timekeeper. |
