A century is one interval the time 100 years in length. When technically a century can refer come any duration of 100 years, most often civilization use the word century in reference to a certain century. These specific centuries start at a date based on the Gregorian calendar, start with the very first century in the year 1 CE.

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Let’s discover the various ways centuries deserve to be defined/occur, and also how the Gregorian calendar serves as the basis because that tracking the i of centuries.


Where does A Century Begin and End?

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While a century can technically be any period of 100 years, from any type of arbitrarily chosen date to a day 100 year in the future, there space two various ways that centuries room usually defined. The strict building and construction of the Gregorian calendar specifies a century together every 100 years start in the year 1 CE, for this reason from 1 CE come 100 CE is the an initial century, and also the second century start in 101 CE and also proceeds come 200 CE. The very same pattern continues onwards, v a new century starting every 101 years. Under this strict construction, the Centennial year is the only year within the century that begins with the century’s number therefore the 20th century only had actually one year v the number 20 in the – the year 2000.

On the various other hand, there is another method a century can be defined. In the general, much more colloquial consumption of the term, centuries are defined by subdividing them into decades and grouping those decades based off of their common digits. As an example, the 21st century will be the years 2000 to 2099. The global Standard for days (the ISO 8601) and also the astronomical year number is numbered system have year zeros within them, and also a consequence the very first century is said to begin with the year zero rather than in 1 CE.

The century device is based upon the Gregorian calendar, i beg your pardon is likewise the most widely provided civil calendar in the entire world. The an initial century begins where the does because of the Gregorian calendar. Let’s research the history of the Gregorian calendar and also see what different sorts of dating systems and 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 even minute owes much to ancient Egyptian civilization. The Egyptian world has its roots in ancient farming societies that based your lives approximately the flooding of the Nile, i m sorry would take place every year. The yearly floods the the Nile helped people determine as soon as to grow their crops, so the was essential to have an idea of when the floods would certainly begin. To store track the the passage of years based upon the yearly Nile flooding, the old Egyptian world invented three various calendars.


One that the calendar they followed was based upon 12 lunar months, and also each of these months began on the an initial day whereby the Crescent moon was no much longer visible at dawn in the east sky. A second calendar, chiefly used for the purposes of governmental tasks, was based on the increasing of the star known as Serpet, and it was listed at the moment that there was normally 365 days in between the helical increasing of this star. This civil year-long calendar was separated into 12 month of 30 job each, with secondary five work attached come the calendar at the finish of the year. The 3rd calendar Egyptian culture used joined the polite calendar and the lunar cycle calendar together. Do the efforts to revolutionary this calendar would certainly be made, through the intentionally of consisting of a leap year, but this change wouldn’t happen until the rule of Emperor Augustus in around 31 BCE, who let the roman Senate decree that the Egyptian calendar should have actually a leap year consisted of in it.

Calendars and also timekeeping would continue to get more sophisticated over the following century or so, and around the year 127 CE, Hipparchus of Niceae proposed the the day should be divvied up into 24 equal hours. An additional philosopher, Claudius Ptolemeus, would later divide those hours into 60 minute apiece. Ptolemeus would likewise create a brochure of the positions of the stars and various constellations, noting down these location in an excellent detail. These star charts and tables would later inform the improvement of the Julian calendar by Gregory XIII in 1582, The occasion responsible for producing the Gregorian calendar.

The development Of The Gregorian Calendar

Around 1572 Pope Gregory XIII was informed that the church was experiencing a dilemm with the existing calendar system. Easter’s date of observation is based on the vernal equinox, the very first day of spring, and the i of year on the modern calendar system meant the the day of Easter’s celebration was being shifted ever backwards. Together a result, the holiday was being celebrated too early in March.

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Photo: Geralt via Pixabay, CC0

At this point, the church was still utilizing the Julian calendar, the calendar initially established by Julius Caesar during his regime in the year 46 BCE, which at this point was over 1600 year old. Caesar had actually made changes to the Egyptian calendar, acquisition the 365 days the the calendar was based around and also making a correction come a calendar based on 364 1/4 days, which is exceptionally close come the length of the tropical year, the dry year gift the quantity of time that takes for the earth to revolve roughly the sunlight once. The calendar denote by Caesar was typically 365 job in length, however every 4 years there was an extra day added to the calendar, a leap day in a leap year.

While the calendar describe by Caesar was fairly accurate, that still wasn’t precise enough due to the fact that a full tropical year is actually 365 days and also five hours, 48 minutes, and 46 seconds long. This means that the calendar describe by Caesar was roughly 11 minutes and 14 secs off. While this may seem prefer a tiny amount, it intended that the calendar would be turn off by a full day within 128 years. These errors had accumulated such that by the moment of Pope Gregory XIII, the calendar to be a complete 10 days off. For this reason, Pope Gregory 13 decided that the existing calendar mechanism must be changed, and astronomers operated to build a new calendar that would certainly be much more accurate 보다 the Julian calendar – this brand-new calendar gift the Gregorian calendar.


The new Gregorian calendar mandated the years would continue to be 365 days long, with an additional day added every four years, other than there could be no leap years on years which ended in 00 – uneven that year to be divisible by the number 400. For this reason while the years of 1600 and also 2000 would have a leap day, the year 1700, 1800, 1900, and 2100 wouldn’t be leap years. This new calendar system was much much more accurate 보다 the Julian calendar, in fact, current scientists only need to include a leap second every few years to store the calendar aligned through the tropical year.

Pope Gregory XIII mandated the the correction because that the Julian calendar it is in immediate, with 10 job taken off the calendar because that the year. In various other words, October 4, 1582, would certainly be flourished by October 15, 1582. Pope Gregory XIII additionally decreed the the brand-new year would currently start on January 1, whereas it had previously started on march 25. Furthermore, the technique of determining Easter’s day would it is in changed.

As you can expect, over there was some resistance come this huge change. Numerous countries were no willing or simply not prepared to adjust the calendar. Furthermore, through 1582 the Catholic Church no longer had actually the government it once had in Europe, thanks to the spread of Protestantism transparent the 1500s. Initially, just a handful of countries, including Portugal, France, and Italy make the readjust to the calendar. Progressively over the food of the following centuries, other nations would make the move to the Gregorian calendar. In 1584, Belgium, the Netherlands, and also Catholic Germany make the switch, while protestant Germany and also Denmark would make the move in 1704. Good Britain and also the colonies under its dominion would readjust their calendar in 1752, and Sweden would change its calendar the following year. Japan finished up adopting the Gregorian calendar in 1873 as component of the westernization that occurred during the Meiji era. Egypt would readjust its calendar in 1875, and between the year of 19 12 and 1917, Albania, Bulgaria, Latvia, Estonia, Lithuania, Turkey, and Romania would certainly all readjust their calendars. Greece switched to making use of the Gregorian calendar in the year 1928, and also China would take on the Gregorian calendar together late as 1949.

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Many nations in the civilization still have actually their own unique calendar solution that they might use in addition to the Gregorian calendar. For instance, Japan has a system of counting the years that uses details eras or periods based on the life that the Emperor. This device is provided in conjunction v the Gregorian calendar in Japan.


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