February-29th-CalendarOnce upon a time, there was no such thing as the month of February. Februarius, as it was originally called, was invented around 700 BC by Numa Pompilius, the second king of Rome. The month was named for Februa, a festival of purification probably originating from Sabine culture. (The Sabines were one of many tribes that lived in ancient Italy) Februa fell on February 15. Even then, February had 28 days, although most months had an odd number of days because that was believed to be lucky.

Because the calendar was 355 days, which is not the exact same length as the solar year, it was necessary to sometimes add a month between February and March, known as the mensis intercalaris. (As a side note, Plutarch, a famous writer in the first century, referred to the intercalary month as Mercedonius.) Years with that extra month would be 377 or 378 days. But the system had its shortcomings. Evidently, the decision about which years needed an extra month was often made for political reasons, allowing political officials to stay in office for an extra month. And the common people didn’t necessarily know ahead of time, with the result that it was hard to keep track of the date. Clearly, calendar reform was in order.

The Julian calendar was introduced by Julius Caesar in the year now known as 46 B.C. That particular year is called the Year of Confusion because he made the year 445 days long in order to put all the seasons back where they belong in the calendar. Then, in 45 B.C., things were back on track with a 365-day year. Even then, there was such as thing as leap day, owing to the fact that the Earth actually takes about 365.25 days to orbit the sun. But “about” isn’t good enough. Every year, a discrepancy of 11 minutes and 14 seconds was added.

By 1582, this discrepancy had added up so much that Pope Gregory XIII solved it by deleting ten days during October. It was also Pope Gregory XIII who determined that February was the month to gain an extra day during leap year. He was even responsible for the terms “leap year” and “leap day”.  In order to keep that discrepancy from continuing to occur, leap day no longer occurs in years ending with 00 unless they are divisible by 400. Thus, 2000 was a leap year, but 1900 was not and 2100 will not be. This results in leap years occurring at the right frequency to keep the average length of the year accurate… almost. The Gregorian calendar still has an extra 26 seconds per year.

February 29 St BrigidBecause of its infrequency, a number of legends and customs have arisen around leap day. According to Irish legend, St. Brigid and St. Patrick agreed that on leap day, women can propose to men. In some parts of Europe in the middle ages, if a man refuses a woman’s proposal on leap day, he must buy her twelve pairs of gloves to hide the embarrassment of her lack of an engagement ring. In Scotland, it is supposedly unlucky to be born on leap day, and in Greece, it is unlucky to get married on leap day, or even in a leap year.

Whatever you do to celebrate this extra day in the calendar, have a happy leap day!