Whether you’re using a paper or electronic calendar, it’s going to be the same calendar that’s been in use since 1582. The same primary Calendar has been used for hundreds of years — and is the most commonly used calendar in the world today. The Calendar is called the Gregorian Calendar. Because this is the calendar that we use day in and out — we felt that we would be remiss if you didn’t know the following 18 Gregorian calendar facts.
1. There are 12 irregular months.
The Gregorian calendar is a solar calendar that’s based on a 365-day typical year, with each year being divided into 12 months. However, these months are of irregular lengths. That’s because 11 of them either contain 30 or 31 days, with February being the exception. The second month of the year has 28 days during the common year. But, every four years or so, there’s a leap year that gives February an extra — or intercalary– day.
Additionally, the days of the year in the Gregorian calendar are broken into seven-day weeks. The weeks are numbered from one to 52, with the occasional 53 weeks. In most of the world, it’s the standard to start each week on Monday. There are, however, a couple of outlier countries, like the United States and Canada — that kick off their weeks on Sunday.
2. The original goal of the Gregorian calendar was to change the date of Easter.
Pope Gregory XIII introduced the Gregorian calendar in 1582. Before this, Europe used the Julian Calendar. The Julian Calendar was a complicated lunar calendar that was put into effect by Julius Caesar in 46 B.C. However, the system was flawed. It miscalculated the length of the solar year by 11 minutes. Over the years, the Julian calendar didn’t sync with the seasons — which became noticeable in the 1570s producing a calendar that was off by ten days.
Supposedly this fact concerned Gregory, but why? As Jennie Cohen explains on History.com, “it meant that Easter, traditionally observed on March 21, fell further away from the spring equinox with each passing year.”
3. Pope Gregory didn’t design the Gregorian calendar.
Although Pope Gregory authorized this new calendar, and it’s named after him, he didn’t come up with it on his own. As pointed in a Vox article, he “appointed a commission, led by physician Aloysius Lilius and astronomer Christopher Clavius, to solve the problem.” After five years, fixed the problem.
“First, let’s eliminate those extra ten days and get back on schedule. Okay, those ten days are gone. Next, let’s tweak the system of leap years. We’ll have leap years every four years except on centennial years that aren’t divisible by 400.” That explains why there was a leap year in 2000, but not in 1900, 1800, or 1700. And, it also squashes that misconception that leap year take placed every four years.
Furthermore, “This changed the length of the average year to 365.2425 days. While not spot-on, it’s close enough and more accurate than the Julian calendar.
4. The first printed Gregorian calendar.
Gregory instituted the calendar on February 24, 1582. Just over a month later, on April 3, to be exact, exclusive rights to publish a book explaining the new calendar were granted to Antoni Lilio. The Lunario Novo secondo la nuova riforma became one of the first printed editions of the new calendar in 1582. Vincenzo Accolti in Rome printed it.
Unfortunately, Lilio couldn’t keep up with the demand for printing calendars. As a consequence, his exclusive rights to the calendar were revoked on September 20, 1582. The pope then commissioned this work to Christopher Clavius.
5. After replacing the Julian calendar, the Gregorian calendar faced resistance.
Because Gregory was the pope and all, there wasn’t a problem getting Roman Catholic countries like Italy, France, Spain, and Portugal to adopt the new calendar. But, that wasn’t the case with European Protestants.
The Catholic Chruch didn’t have any power over these states. So, they couldn’t be forced to switch calendars. Protestants were suspicious of the new calendar and viewed it as “a suspicious Catholic intrusion.” Some even believed that it was the work of the Antichrist.
Because of this, the Gregorian calendar wasn’t embraced by these countries until much later. For example, it wasn’t adopted in Germany until 1700 and England in 1752.
6. The Gregorian calendar differs from the solar year by 26 seconds per year.
“Despite Lilius’ ingenious method for syncing the calendar with the seasons, his system is still off by 26 seconds,” explains Cohen. What being off by twenty-six seconds means is that since it’s implementation, “a discrepancy of several hours has arisen.” It’s said that by “the year 4909, the Gregorian calendar will be a full day ahead of the solar year.”
7. Leap days can be traced back to ancient times.
While the Gregorian Calendar is known for its leap years, this idea had been developed by ancient civilizations. The ancient Egyptians are credited from determining the length of a solar year. They even went ahead and adopted a calendar that included an extra day every four years.
It’s believed that Europeans were introduced to this idea after Cleopatra shared this system with Julius Cesar.
8. The Gregorian calendar is useless — well, at least to astronomers.
Useless sounds a bit harsh. But, there’s a scientific reason behind the statement — and I’m not biased against the Gregorian calendar.
As noted by the Galileo Project, “the Gregorian Calendar is useless for astronomy because it has a ten-day hiatus in it. To calculate positions backward in time, astronomers use the Julian Date.”
9. January 1 and the start of a new year.
Believe it or not, January 1 has often been considered the start of the new year. When Cesar introduced his calendar back in 45 B.C.E., he made 1 January the start of the year. Noted by WebExhibits, January 1 “was always the date on which the Solar Number and the Golden Number were incremented.”
“However, the church didn’t like the wild parties that took place at the start of the New Year, and in C.E. 567, the council of Tours declared that having the year start on 1 January was an ancient mistake that should be abolished.”
The abolished observance didn’t last. But, this is where things get confusing. Some argue that Pope Gregory reinstated January 1 as the start of the new year, instead of March 25. Others believe that this is a myth. According to WebExhibits, this misconception “started because in 1752 England moved the start of the year to 1 January and also changed to the Gregorian calendar. But in most other countries, the two events were not related.” Scotland is one example of this. Although Scotland changed to the Gregorian calendar with England in 1752, the start of the new had been January 1 since 1600.
10. Double date.
A double-date isn’t scheduling a date with you and your significant other with another couple. The double-date here has to do with the transition from the Julian to the Gregorian calendar. The shift from the Julian Calendar t the Gregorian Calendar is commonly referred to as a dual-date to prevent any confusion.
Regardless of the name — from 1582 to around 1923, there were two calendars in use. Both the Julian and Gregorian calendars were used. Not every country had moved to the Gregorian Calendar, and because of this problem — it was necessary to indicate the date for both calendars. For example, “10/21 February 1750/51.”
As further explained by Matt Rosenberg on ThoughtCo. “dates were written with O.S. (Old Style) or N.S. (New Style) following the day, so people examining records could understand whether they were looking at a Julian date or a Gregorian date.” One famous example of this is George Washington. He was born on February 11, 1731 (O.S.), but “his birthday became February 22, 1732 (N.S.) under the Gregorian calendar.”
“The change in the year of his birth was due to the change of when the change of the new year was acknowledged,” adds Rosenberg. “Recall that before the Gregorian calendar, March 25 was the new year, but once the new calendar was implemented, it became January 1. Washington was born between January 1 and March 25, so the year of his birth became one year later in the switch to the Gregorian calendar.”
11. Days have been “lost” forever.
When Pope Gregory issued “Inter Gravuissimus,” a papal bull explaining how he was changing time, in February 1582, that meant ten days would have to be removed from the calendar. Remember, because the Julian calendar wasn’t accurate, it had fallen behind over the centuries.
When the new calendar was made official on October 4, 1582, people woke up the next day to a new date; October 15. Thankfully, the day of the week didn’t change because it was a Friday.
1582 isn’t the only time in history that days vanished from a calendar. When England switched to the Gregorian Calendar on September 2, 1752, they woke up on September 14. And, because we were still a colony, this meant the occasion happened in the States as well.
There are also more recent examples. In Alaska, October 6, 1867, was followed by October 18, 1867. The reason was that up until this point, Alaska was a part of Russia — a country that didn’t use the Gregorian Calendar.
Russia switched in 1918 and Greece in 1923. Because these countries waited so long, they had to skip over 13 days.
12. There was once February 30.
When Sweden swapped the Julian calendar for the Gregorian they didn’t sacrifice days like other countries. Instead, they placed a February 30 on their calendar. The plan was to omit leap days over the next 40 years to remove those extra ten days.
The plan didn’t work out well, and in 1712, the Great Northern War broke out. The war as so brutal that no one remembered to remove the following two leap days. The powers that be, at that time, went back to the Julian calendar in 1712. Finally, we jumped over to the Gregorian calendar in 1753 for good, and we never saw February 30 again.
13. Leap years could mean an extra paycheck (or a pay cut).
As written in the Wall Street Journal, “While most years are 52 weeks long plus one day, leap years have 52 weeks and two extra days.” So, if you’re paydays fall into either of these days, then you’ll get an extra paycheck.
Before you start thinking about how you’re going to spend that extra cash, most businesses have a loophole. “To compensate for the extra payday, companies will likely reduce salaried individual paychecks throughout the year to ‘pay’ for the extra paycheck,” says the American Payroll Association. “Most salaried individuals are promised an annual salary, not a specific amount each paycheck.”
14. Days of the week.
Ever wondered why there are seven days a week? The Gregorian calendar followed the lead of ancient Babylon. Since 600 BCE, the seven-day week was based on the phases of the moon. The last day was set aside as a holy day for the new moon phase.
Eventually, the days of the week were named after Greek gods; Ares, Hermes, Zeus, Aphrodite, and Cronus. The Romans substituted these names with their equivalents; Dies Solis, Dies Lunae, Mars, Mercury, Jupiter, Venus, and Saturn.
The names that we use today, however, actually come from Germanic and Norse gods. For example, Tuesday (Tiw), Wednesday (Woden), Thursday (Thor), and Friday (Freia).
15. Origins of the names of the months.
The Gregorian calendar continued to use the months found in the Julian calendar, which were named mainly after Roman gods. But, also historical figures and Latin terms.
- January: named after Janus
- February: in honor of Februus
- March: derived from Mars
- April: chosen from Aphrodite
- May: in honor of Maia
- June: named after Juno
- July: selected after Julius Caesar
- August: named after Augustus Caesar
- September: seven in Latin
- October: from the Latin for eight
- November: nine in Latin
- December: from the Latin for ten
16. Other calendars are more accurate.
Despite its popularity and use, National Geographic states that the Gregorian calendar isn’t the most accurate. For example, “The Persian calendar, the official calendar of Iran and Afghanistan, requires fewer adjustments (such as leap years).” Some even claim the Maya calendar is more precise than the Gregorian calendar.
17. Late adopters.
Most countries adopted the Gregorian calendar hundreds of years ago. But, there were a few stragglers. Slower to embrace the change were China (1912), Bulguria (1916), Russia (1917), Greece (1923), and Turkey (1926).
Most recently, Saudi Arabia replaced the lunar-based Hijri Calendar with the Gregorian in 2016. Although the country was 434 years late, they always say it’s better late than never.
18. Recent Gregorian calendar reforms have failed.
As we’ve already said, the Gregorian is not perfect. Because of this, there have been many attempts to reform the calendar, so that’s more accurate. Additionally, technology continues to push the calendar to evolve. But, all of these attempts to redesign the calendar have failed.
Here are some notable examples of failed Gregorian calendar reforms:
- Following the French Revolution, many pushed for a 10-day long calendar that wasn’t associated with religion.
- Auguste Comte, in 1849, created the Positivist calendar, which renamed the months after historical figures like Moses and Aristotle.
- In 1902, Moses B. Cotsworth designed a calendar with 13 months containing 28 days each. Cotsworth’s idea had some hiccups with leap years.
- Eastman Kodak also embraced the 13-month calendar and used it from 1924 to 1989.
In 2011, Richard Conn Henry, an astrophysicist at Johns Hopkins University and former deputy director of NASA’s astrophysics division, teamed up with economist Steve Hanke. They created the Hanke-Henry Permanent Calendar that would create a fixed calendar. Every calendar seems to have a problem, and the Henry/Hanks calendar meant that every year, the date falls on the same exact same day.
Ever thought of making a calendar? We have. We are Calendar — but we stick with making you more productive within the calendar year.