One of my earliest memories is of my first birthday. I remember it with unusual clarity because I was four years old at the time. This year is a “Golden Birthday:” I will have my 12th birthday in 2012 but I was not born in 2000.
Leap year has been around since it was ordered by Ptolemy III in 238 B.C. because calculations for an accurate solar year were beginning to be determined. A solar year is 365 days, 5 hours, 49 minutes, and roughly 12 seconds. The figure is just short of 6 hours, and six times four is 24, which is the number of hours in a day—so if you add an extra day every four years (creating leap year) the calendar becomes fairly accurate.
But not accurate enough.
The calendar would run too fast if further modifications were not made. So every century year (like 1700, 1800, or 1900) does not have a leap year. But every fourth century year, like 1200 and 1600, there is a leap year. I had a birthday in 2000 and did not take it for granted--it was required to make our calendars reasonably accurate. I was born on a day that was an indefinitely extended truce between the cosmos and our need for a workable calendar.
What is it like to have a birthday on leap year?
It means that one pays attention to exceptions. It is also a four-year cycle that encodes part of my life with its meaning. I can flip through them as quickly as a mahjong player sorts tiles and remember where I was and who I spent time with on each of them. Since I have lived in so many places this has been of value.
Most people born on leap year have been rejected by computers at several points in their lives. Many have been asked to have drivers licenses renewed before February 29 of a year that only had 28 days in February, because the expiration was linked to a birthday without consideration of the uniqueness of their birthday. But before computerization it seemed less common to run into folks with a birthday on leap year. I once received a free cake simply by proving by birthday to a store owner. He never met someone who was born on such a strange day. I told him I planned it.
The composer Gioachino Rossini was born on leap year in 1792. He would have been 52 on his 12th birthday in 1844, and was long since retired. That is four years older than I am on my 12th birthday. Rossini was unlucky enough to have passed the threshold of 1800 and would therefore not have had his second birthday until he was 12 in the year 1804. But just a few birthdays later and he was already immortal; known forever as the composer of Tancredi and L'italiana in Algeri.
Leap year also figured in the plot of Gilbert and Sullivan’s comic opera “The Pirates of Penzance.” Frederic is required to be an apprentice until his 21st birthday. When he turns 21 and completes his apprenticeship he meets his lover Mable, but was then told by the pirates that since he was born on leap year he owed them another 63 years. If the pirates did not know about the century rule Frederic might have gotten out four years early.