A century is an interval that time 100 years in length. While technically a century have the right to refer to any period of 100 years, most often civilization use words century in reference to a particular century. These details centuries begin at a date based upon the Gregorian calendar, beginning with the first century in the year 1 CE.

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Let’s check out the different ways centuries deserve to be defined/occur, and how the Gregorian calendar serves as the basis for tracking the i of centuries.


Where go A Century Begin and also End?

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While a century can technically be any duration of 100 years, from any arbitrarily chosen date to a day 100 years in the future, there room two different ways that centuries room usually defined. The strict construction of the Gregorian calendar defines a century together every 100 years beginning in the year 1 CE, for this reason from 1 CE to 100 CE is the very first century, and also the 2nd century beginning in 101 CE and also proceeds come 200 CE. The exact same pattern proceeds onwards, with a brand-new century beginning every 101 years. Under this strictly construction, the Centennial year is the just year in ~ the century that starts with the century’s number for this reason the 20th century only had actually one year through the number 20 in it – the year 2000.

On the various other hand, over there is another method a century have the right to be defined. In the general, much more colloquial usage of the term, centuries are characterized by subdividing them into decades and grouping those years based turn off of their shared digits. Together an example, the 21st century will certainly be the year 2000 to 2099. The global Standard for dates (the ISO 8601) and also the expensive year numbering system have year zeros within them, and also a repercussion the very first century is said to start with the year zero fairly than in 1 CE.

The century system is based on the Gregorian calendar, i beg your pardon is also the most widely offered civil calendar in the entire world. The very first century starts where it does as result of the Gregorian calendar. Let’s research the history of the Gregorian calendar and also see what different sorts of dating systems and also calendars came prior to it.

Before The Gregorian Calendar

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The method our culture divides time right into years, days, hours and also even minutes owes much to ancient Egyptian civilization. The Egyptian civilization has its roots in ancient agricultural societies who based their lives about the flooding of the Nile, i m sorry would occur every year. The yearly floods the the Nile helped civilization determine once to grow their crops, so it was important to have an idea of when the floods would certainly begin. To save track the the passage of years based upon the yearly Nile flooding, the old Egyptian civilization invented three various calendars.


One of the calendars they followed was based on 12 lunar months, and each of these months began on the first day where the Crescent moon was no longer visible at dawn in the eastern sky. A second calendar, chiefly offered for the functions of administrative tasks, was based upon the rising of the star recognized as Serpet, and also it was detailed at the time that there was usually 365 days in between the helical rising of this star. This polite year-long calendar was divided into 12 month of 30 work each, with second five work attached come the calendar in ~ the finish of the year. The third calendar Egyptian society used joined the civil calendar and also the lunar cycle calendar together. Make the efforts to reform this calendar would be made, with the on purpose of including a leap year, yet this readjust wouldn’t happen until the dominion of Emperor Augustus in about 31 BCE, that let the roman inn Senate decree that the Egyptian calendar should have a leap year included in it.

Calendars and timekeeping would proceed to get much more sophisticated end the following century or so, and also around the year 127 CE, Hipparchus that Niceae proposed the the day should be divvied up right into 24 equal hours. One more philosopher, Claudius Ptolemeus, would later divide those hours into 60 minute apiece. Ptolemeus would additionally create a directory of the positions of the stars and also various constellations, noting under these location in an excellent detail. These star charts and also tables would later inform the reformation of the Julian calendar through Gregory XIII in 1582, The occasion responsible for creating the Gregorian calendar.

The development Of The Gregorian Calendar

Around 1572 Pope Gregory XIII was educated that the church was suffering a situation with the existing calendar system. Easter’s day of monitoring is based upon the vernal equinox, the very first day of spring, and the i of years on the modern-day calendar system meant the the date of Easter’s celebration to be being shifted ever backwards. Together a result, the vacation was being celebrated too early in March.

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Photo: Geralt via Pixabay, CC0

At this point, the church to be still making use of the Julian calendar, the calendar initially established by Julius Caesar during his regime in the year 46 BCE, which at this allude was end 1600 year old. Caesar had made adjustments to the Egyptian calendar, taking the 365 days the the calendar to be based around and also making a correction to a calendar based upon 364 1/4 days, which is extremely close come the length of the dry year, the tropical year gift the quantity of time the takes because that the earth to revolve around the sunlight once. The calendar describe by Caesar was typically 365 job in length, but every four years there was an extra day added to the calendar, a leap job in a leap year.

While the calendar denote by Caesar was quite accurate, the still wasn’t exact enough because a full tropical year is in reality 365 days and also five hours, 48 minutes, and also 46 secs long. This means that the calendar describe by Caesar was approximately 11 minutes and 14 secs off. When this might seem like a tiny amount, it meant that the calendar would be off by a complete day within 128 years. These errors had accumulated such the by the time of Pope Gregory XIII, the calendar to be a complete 10 job off. Because that this reason, Pope Gregory 13 determined that the present calendar system must be changed, and also astronomers worked to construct a new calendar that would certainly be an ext accurate 보다 the Julian calendar – this new calendar gift the Gregorian calendar.


The new Gregorian calendar mandated the years would proceed to be 365 work long, with one more day added every 4 years, other than there could be no leap years on years which finished in 00 – unless that year was divisible by the number 400. So while the year of 1600 and also 2000 would have actually a leap day, the year 1700, 1800, 1900, and also 2100 wouldn’t it is in leap years. This new calendar system was much much more accurate 보다 the Julian calendar, in fact, present scientists only require to include a leap second every couple of years to store the calendar aligned v the dry year.

Pope Gregory XIII mandated that the correction because that the Julian calendar be immediate, through 10 days taken turn off the calendar because that the year. In other words, October 4, 1582, would certainly be prospered by October 15, 1582. Pope Gregory XIII also decreed the the brand-new year would currently start on January 1, whereas it had actually previously started on march 25. Furthermore, the technique of identify Easter’s date would it is in changed.

As you might expect, there was some resistance come this enormous change. Many countries were no willing or merely not ready to change the calendar. Furthermore, through 1582 the Catholic Church no longer had actually the government it once had actually in Europe, thanks to the spread out of Protestantism throughout the 1500s. Initially, only a handful of countries, including Portugal, France, and Italy make the adjust to the calendar. Progressively over the food of the following centuries, other countries would do the switch to the Gregorian calendar. In 1584, Belgium, the Netherlands, and Catholic Germany made the switch, while good news Germany and also Denmark would certainly make the switch in 1704. Good Britain and also the nests under its preeminence would readjust their calendar in 1752, and also Sweden would change its calendar the complying with year. Japan finished up adopting the Gregorian calendar in 1873 as component of the westernization that emerged during the Meiji era. Egypt would change its calendar in 1875, and also between the year of 19 12 and 1917, Albania, Bulgaria, Latvia, Estonia, Lithuania, Turkey, and Romania would certainly all change their calendars. Greece switched to making use of the Gregorian calendar in the year 1928, and China would take on the Gregorian calendar as late together 1949.

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Many nations in the human being still have actually their own distinct calendar solution that they might use in addition to the Gregorian calendar. For instance, Japan has actually a device of counting the years that uses specific eras or periods based upon the life of the Emperor. This system is supplied in conjunction with the Gregorian calendar in Japan.


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