How Long Is A Century In Years?

How long is a century? A century is an interval of time 100 years in length. While technically a century can refer to any period of 100 years, most often people use the word century in reference to a specific century. These specific centuries start at a date based on the Gregorian calendar, beginning with the first century in the year 1 CE.

Let’s explore the different ways centuries can be defined/occur, and how the Gregorian calendar serves as the basis for tracking the passage of centuries.

Where Does A Century Begin And End?

While a century can technically be any period of 100 years, from any arbitrarily chosen date to a date 100 years in the future, there are two different ways that centuries are usually defined. The strict construction of the Gregorian calendar defines a century as every 100 years beginning in the year 1 CE, so from 1 CE to 100 CE is the first century, and the second century starts in 101 CE and proceeds to 200 CE. The same pattern continues onwards, with a new century starting every 101 years. Under this strict construction, the Centennial year is the only year within the century that begins with that century’s number so the 20th century only had one year with the number 20 in it – the year 2000.

On the other hand, there is another way a century can be defined. In the general, more colloquial usage of the term, centuries are defined by subdividing them into decades and grouping those living room design in the philippines decades based off of their shared digits. As an example, the 21st century will be the years 2000 to 2099. The International Standard for dates (the ISO 8601) and the astronomical year numbering system have year zeros within them, and a consequence the first century is said to start with the year zero rather than in 1 CE.

The century system is based on the Gregorian calendar, which is also the most widely used civil calendar in the entire world. The first century begins where it does due to the Gregorian calendar. Let’s examine the history of the Gregorian calendar and see what alternative sorts of dating systems and calendars came before it.

Before The Gregorian Calendar:

The way our society divides time into years, days, hours and even minutes owes much to ancient Egyptian civilization. The Egyptian civilization has its roots in ancient agricultural societies who based their lives around the flooding of the Nile, which would occur every year. The yearly floods of the Nile helped people determine when to grow their crops, so it was important to have an idea of when the floods would begin. To keep track of the passage of years based on the yearly Nile flooding, the ancient Egyptian civilization invented three different calendars.

One of the calendars they followed was based on 12 lunar months, and each of these months started on the first day where the Crescent moon was no longer visible at dawn in the eastern sky. A second calendar, chiefly used for the purposes of administrative tasks, was based on the rising of the star known as Serpet, and it was noted at the time that there was usually 365 days between the helical rising of this star. This civil year-long calendar was divided into 12 months of 30 days each, with an additional five days attached to the calendar at the end of the year. The third calendar Egyptian society used joined the civil calendar and the lunar cycle calendars together. Attempts to reform this calendar would be made, with the intention of including a leap year, but this change wouldn’t happen until the rule of Emperor Augustus in approximately 31 BCE, who let the Roman Senate decree that the Egyptian calendar should have a leap year included in it.

Calendars and timekeeping would continue to get more sophisticated over the next century or so, and around the year 127 CE, Hipparchus of Niceae proposed that the day should be divvied up into 24 equal hours. Another philosopher, Claudius Ptolemeus, would later divide those hours into 60 minutes apiece. Ptolemeus would also create a catalog of the positions of the stars and various constellations, noting down these positions in great detail. These star charts and tables would later inform the reformation of the Julian calendar by Gregory XIII in 1582, The event responsible for creating the Gregorian calendar.

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