The Gregorian Calendar-Introduction,History & Facts

Gregorian Calendar, which is also sometimes referred to as “New Style Calendar. It is the most followed calendar around the globe, and is still in use. Gregorian Calendar was introduced by Pope Gregory XIII in the year October 1582. This date is from Julian calendar, and one say that Gregorian calendar is an advanced and modified version of Julian calendar, and so they have many commonalities.

History Of Gregorian Calendar

Before Gregorian calendar, the Julian Calendar used to be followed. The Julian calendar was then modified into Gregorian calendar by Pope Gregory, for the two basic reasons.

  1. Although the Julian calendar was more detailed, it showed the average solar year incorrectly and that started to cause problems, especially regarding to try, to track back into history, as many dates were missed in this time period. Julian calendar used to show 365.25 days which was an overestimate of one day, per each century. And so Gregorian calendar deducted that detail, to avoid confusion.
  2. Secondly, there were quite a bit too many leap days, that were introduced by Julian calendar and they were collapsing all the tracking back to the history, causing problems for especially monks and popes. The dates, seasons and weathers were not in the right order, the dates were not exactly as an occasion and they were confused whether when can they celebrate Easter?

These reasons made the popes rethink and hence they modified the Julian calendar into Gregorian calendar, by making some changes that were necessary.

Pre-Gregorian Calendar

Before Gregorian calendar was in shape, Julian Calendar used to be followed by many countries around the globe. It was introduced by Julius Caesar ( in 45BCE). Julian calendar replaced Roman calendar, Roman calendar on the other hand was a lunar calendar. And it was getting very difficult for people to track the months or dates as it was all dependent on the phases of moon. And so to overcome this problem Julian calendar was adopted. At that time February was the last month of the year, and leap day used to be 24th of February.

Leap Days Were Introduced

The origination of leap days started since Julian calendar. Although there was no leap day in the first year of this calendar so they could reform the errors but then afterwards, every four years would be a leap year for Julian calendar.

Gregorian Calendar Spread around The Globe, With Time

The Europeans, specifically the Catholic nations of Europe adopted the Gregorian calendar. As it was well suited to their history and yearly occasions. Then later on, the Eastern Orthodox countries started to follow this calendar. Due to the economical dominance of western, Gregorian calendar was successfully being adopted around the globe, while Greece was the last European country to adopt it.

Great Facts About Gregorian Calendar (Western Calendar)

1.   Consists Of 12-Non-Symmetrical Months

Gregorian Calendar is a solar calendar. It consists of 12-months and 365 days. All the 11 months have either 30 or 31 days, but February being a leap month only have 28 days, during common years. After every four months, there is a leap year when 1 day is added to the month of February, and that is 29th of February, that year will be then 366 days long.

2.   Representation Of Dates And Time

In Gregorian calendar, date and time shall be written in the following manner; “ ISO 8601:2004”.

3.   Pope Was Not The Designer Of This Calendar

Although this calendar was introduced by Pope and is named after him, he himself did not design this calendar, and it wasn’t something he came up with, all alone. He appointed the commission, which was led by an astronomer Christopher Clavius and a Physician Aloysius Lilias. It took them five years of time, to overcome this problem and introduce Gregorian calendar.

4.   Astronomers Still Use Julian Calendar

Although Lilias synced the calendar with seasons, there is still 26 seconds  difference and because of this, Galileo cleared out that Gregorian calendar is not in the use of astronomers and they still use Julian calendar as it works more accurately for them.

5.   10 Lost Days

As the Pope needed to modify Julian calendar into Gregorian because Julian calendar due to its in accuracy was falling behind in history. They had to vanish 10 days from the newly introduced calendar as to balance it. When Gregorian calendar was introduced on 4th of October, 1582, then the next day people woke up to 15th of October 1582, 10 days vanished from history.

What Calendar To We Use Now?

The time now or you can say the since 1582 till now, we have been using Gregorian calendar. It is widely used around the globe and there might be a little disagreement with some countries that prefer lunar calendars, for different purposes. Some countries follow more than one calendar as per there interest and need.

Which Calendar Is Followed By The Military?

If you have this question in mind, then it is a relevant question to ask as military has their own clock to track time, is there a separate calendar for them?

No, they do not have any other calendar and they follow The Gregorian Calendar, just like us. As this calendar is more simpler and easy to follow.

Did You Know?

Although Gregorian calendar was adopted around the globe but it took three centuries to finally be accepted by most of the regions.

Year of SwitchCountryDays Removed
1582France , Italy, Poland, Portugal and also Spain10 days
1583Austria, Germany (Mostly Catholic states)10 days
1587Hungary10 days
1610Germany (specifically Prussia)10 days
1700Germany (Protestant side), Switzerland (Protestant localities)10 days
1752United Kingdom (and colonies)11 days
1872/1873Japan12 days
1916Bulgaria13 days
1918Estonia, Russia13 days
1923Greece13 days
1926/1927Turkey13 days

These are only the list of those countries that officially used Julian calendar before this calendar was introduced. Other countries that switch from other calendars are not placed in this list.