Facts

The Surprising History Behind Leap Year

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For a day that happens only every four years, and in rare cases separated by eight years, Feb. 29 has a lot going on — everything from science to superstition.

Earth’s yearlong revolution around the sun isn’t tidy: It takes 365.24219 days to complete the circle, leaving us with some spare change that adds up to an extra day almost every four years. Because Earth’s annual revolution is a little short of a quarter of a day, there are rare occasions when there is no leap year. Years that are divisible by 100 but not by four aren’t leap years. The turn of the 21st century — 2000 — was a leap year, but the years 1700, 1800 and 1900 weren’t, and there won’t be one in 2100.

Leap year’s origins go back to ancient astronomy. The Egyptians created a 365-day solar calendar but realized it wasn’t accurate and also maintained a lunar calendar to compensate for the extra time. In 46 B.C., during Roman emperor Julius Caesar’s reign, an extra day — Feb. 29 — was added to the calendar every four years. Sixteenth-century astronomers refined the calendar to account for the 365.24-day year in the Gregorian calendar still used today.

People born on a leap year — also known as leaplings or leapers — sometimes have a tough time of it. Most of their lives, they have to celebrate their birthday on another day — usually Feb. 28 or March 1, and sometimes both. Some face bureaucratic hassles with getting driver’s licenses and insurance policies. Facebook had to make an adjustment so that leapling users have a Feb. 29 birthday option when creating a profile: still, three out of four years, their Facebook friends don’t know it’s their birthday.

Being a leap day baby is “comical and frustrating,” said Raenell Dawn, a leapling living in Keizer, Ore., who is co-founder of the Honor Society of Leap Year Day Babies, an online club where nearly 11,000 members celebrate their “leapness,” as Ms. Dawn calls it.

“Many leap day babies are sick and tired of hearing the same questions. We’ve got to help the school system embrace leap year day and make it fun in school. This is what you can get me for my birthday: Donate a leap day-themed book to your school library,” she said.

Her group has a website filled with fun facts and artifacts like leap day cards, pictures of pets born on leap day and merchandise such as children’s books, T-shirts and cards, along with an online community for leaplings. The group is also active in advocacy initiatives, including encouraging and helping companies to adjust their software to accommodate leap day.

Famous leaplings include 16th-century Pope Paul III, composer Gioachino Rossini, bandleader Jimmy Dorsey, singer Dinah Shore, actors Ken Foree and Dennis Farina, hockey player Cam Ward and rapper/actor Ja Rule. A fictional celebrity — Superman — was born Feb. 29, according to references in the comic books.

Feb. 29 is most famously associated with a tradition in which women were allowed to propose marriage on that rare date. The custom is thought to have originated in Ireland, where legend has it that St. Bridget petitioned St. Patrick for a day when women could pop the question. One tradition required men who turned down such proposals to buy the women gloves so they could hide the fact that they had no engagement ring.

Adding an extra day disrupts the rhythms of nature’s cycle, and many old rural superstitions have clouded leap year. “Leap year was ne’er a good sheep year,” according to an old Scottish proverb.

“Nothing shall be built, planned or planted in a leap year; it does not prosper,” according to “Encyclopedia of Superstitions, Folklore and the Occult Sciences of the World.” “The whole vegetable world is affected by the influences of leap year. The peas and beans grow the wrong way in their pods, and seeds are set in quite the contrary way to what they are in other years.”

Babies born Feb. 29 were considered unlucky and not just because they were cheated out of three-quarters of their birthdays. They were thought to be hard to raise and prone to illnesses. The Greeks thought that getting married or starting any kind of contractual relationship in a leap year was a bad idea.

Feb. 29, 1504, was an auspicious date. When the local Indians cut off food provisions to his crew, Christopher Columbus, who knew that there was a lunar eclipse happening Feb. 29, told them that God was unhappy with them for withholding food and would place a sign in the skies, followed by famine and pestilence. “When, then at seven o’clock, the earth was still and the moon appeared red like fire and a dark film came creeping over her face, abject fear seized upon the poor Indians,” wrote John Boyd Thacher in “Christopher Columbus: His Life, His Work, His Remains.” The food supplies started flowing again.

The 1940 Academy Awards were handed out on Feb. 29. It was a milestone Oscar year: Hattie McDaniel became the first African-American to win for her work as supporting actress in “Gone With the Wind.”

Fast forward to leap year 2016. Chevrolet has launched a social media campaign with the Twitter hashtag #DayItForward. It is urging people to use the extra day to do an unexpected act of kindness — something for someone else that will make their lives better or happier, like buying a stranger a cup of coffee.

Ms. Dawn also encourages non-leaplings to seize the extra day and make it meaningful. “It’s everyone’s extra day,” she said. “Do something good with it. Take yourself on a vacation. Take the day off. Volunteer at the school or hospital.

“Use it wisely. Don’t let it just go by and waste it. That’s good advice for any day.”