Thank the Catholic Church for your leap year
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Why is there a leap year?

Thank the Catholic Church for your leap year

Where did your calendar come from? Not your daughter’s One Direction calendar or your son’s Dr. Who calendar. Those came from the mall. We also don’t mean the one your local funeral parlor sponsors for your parish (not that we’re not grateful, funeral parlors, but we hope you’re not sitting by the phone waiting for our call…that’s a little creepy).

We’re talking about the calendar at the heart of all those iterations: the collection of months and days we all build our lives around. Why make a big deal about it? Because it’s a Catholic thing! The Gregorian Calendar—named after Pope Gregory XIII and why there is a leap year, who introduced it to the world in 1582 A.D.

Wasn’t there a calendar before 1582?

Of course there was. There were plenty of calendars depending on your culture and country. But for centuries, since Imperial Rome was in charge of pretty much everything, the Roman calendar was the most widely used key to chronology in the ancient world. Around 45 B.C., the one-and-only Julius Caesar had it modified, producing the Julian calendar, which was the calendar of record when Christianity arrived on the scene.

Christianity and Caesar’s calendar coexisted for more than a dozen centuries until the Church got tired of chasing Easter, which kept moving farther and farther from the spring equinox due to an 11-minute miscalculation of the solar year by Caesar’s calendar guys. Easter would eventually wander back, but it would go right back on its way again.

Did the Romans know they were off by a crucial 11 minutes? Evidence suggests they probably did. Did they care? Who knows? Even if they decided to get concerned, was anyone really going to walk up and tell Caesar? “Um. Boss? About all those calendars we’ve got in the warehouse….” Odds are the transcript of the conversation may have ended abruptly, shortly thereafter.

Gregorian Calendar - Pope Francis

Aloysius Lilius “leaps” onto the scene.

In the 1500s the Church set about the task of correcting the calendar so that Easter would stay put; to make that happen, calculations by a man named Aloysius Lilius were put into place. Basically, he changed the way leap years were used. Here’s the basic rule:

Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is.

Got it? Good. Given all of that, if you were born in a leap year and still know how old you are, we’re very impressed.

Everybody’s a critic.

And so, we now had a dandy new Gregorian calendar, created to accurately place the most important day of the Christian year. Great news? Right? But let’s remember what else happened in the 1500s. A little conflagration called the Reformation.

What with the pope’s name being on the calendar and all, some Protestant countries thought Gregory XIII might be pulling a fast one on them, trying to get them Catholic again on the sly. It took a while for people to come around, but eventually, since doing business among countries is easier using a common calendar, most countries did. England and “the colonies” came on board in 1752—but what’s a couple of centuries when you’re dealing with all of time?

Today the world pretty much uses our Catholic Calendar (sorry, we just love saying that) for keeping track of common interests, but there are still plenty of other calendars people keep; the Hebrew calendar is one that Americans tend to be familiar with since many of our countrymen celebrate holy days based on it. And who can blame the people St. John Paul II called “our elder brothers in the faith of Abraham” for wanting to keep a different calendar than their little brothers and sisters?

Gregorian Calendar - Psalms

In case you’re not confused enough.

Remember the good old Julian calendar? Well, our brothers and sisters in Eastern Christianity still use it—one of those lasting symbols of the East-West Christian divide. That’s why we don’t all celebrate Easter on the same Sunday every year.

Whatever day it is according to YOUR calendar, we hope it’s a blessed one. And thanks to the folks at and for providing source material for today’s blog!

Let us hear from you!

Do you have a day of the year that the rest of us don’t celebrate? Something unique to your family or culture? Tell us about it in the com box below.

Jim Moore

Jim Moore

Jim Moore is a freelance writer and the former managing editor of Envoy Magazine. His motto? “Don’t worry. Be Catholic.” You can reach him at
Jim Moore
Thank the Catholic Church for your leap year JohnnyMidnyte

Neat.  Interesting article, thanks for sharing. 

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