A Brief History of Calendars

Some people claim our lives are ruled by calendars.  You've hung them on the wall, given them as presents for family and friends, scribbled notes and other data on them.  In all probability you have rarely been far from a calendar in your entire life.  But did you ever wonder where calendars came from?

In ancient times, as now, calendars were based on astronomical events - either the yearly movement of the sun, or the nearly monthly movement of the moon.  For ancient people, determining the time of the year was a critical component of knowing when to sow crops.  Perhaps the easiest way to watch the turning of the seasons is to watch the moon, which waxes and wanes each month. Unfortunately, since the moon's orbit is not synchronized with the earth's orbit around the sun, depending on a lunar calendar alone would make it difficult to know just when to plant crops.  In addition, the earth travels around the sun in just a tiny bit faster than one year (about a quarter of a day each year) - thus our need for leap years.  And each year, the speed of the earth's orbit varies incrementally, forcing us to change our clocks just slightly each year.

Early farmers couldn't study these incremental changes, but still had to study the sun, and create methods for tracking the days of the year. The very first "calendars" weren't calendars that we would recognize - they were carefully placed rocks, carvings, or structures that allowed early farmers to track the sun's orbit.  Perhaps the most famous example is Stonehenge.

Most historians believe that the first written calendar, based on a lunar cycle, was designed by the Chinese in about 2600 B.C.  This calendar, which names years after animals of the Zodiac, is still in use today.  Another written calendar listing the days of the years was developed by the Babylonians between 2000 and 1000 B.C.E.  This calendar, however, frequently changed.  In some years, for example, the Babylonians would insert random months - making keeping track of time extremely challenging! 

As far as we know, the first standardized written calendar based on a solar year was developed by the ancient Egyptians around 1000 B.C.E.  The Egyptians, noted astronomers, needed an accurate calendar to predict the annual flood of the Nile River and allow people time to make preparations. Their calendar contained 12 30 day months and a five day festival between years, for a total of 365 days per year. Although this calendar did not allow for leap years, its general accuracy made it a basis for most future calendars.

But not all ancient cultures followed the example of the Egyptians - the ancient Greeks, for example, used a lunar calendar that followed a very confusing 19 year cycle.  The Romans kept tinkering with their calendar until Julius Caesar, in 46 B.C., finally reformed the calendar, creating the12 month year that we still use today.  (The month of July was named after him, and the month of August for his successor, Caesar Augustus.)

Counting years, however, remained a problem. Most ancient histories and calendars used the reign of the life of the current ruler - for example, "in the fifteenth year of the Emperor Tiberius-" but when rulers died in the middle of the year, this could be confusing.  In about 523 C.E., Dionysius, a monk, decided to calculate the year of the birth of Jesus Christ and begin counting years from that date. Although his calculations turned out to be wrong by four to seven years, we still use his calculations to count years.

The calendar instituted by Julius Caesar was not quite accurate, and after a number of years, it failed to synchronize with the seasons.  Thus, in 1582, Pope Gregory XIII instituted the Gregorian calendar, which restored the correct dates to the correct seasons - the solar calendar used by most of the world today.  Not everybody immediately caught on to the idea - in fact, Russia did not adopt the new dating system until 1918!

Calendars based on the Moon's orbit are still in use - both the Hebrew and Muslim calendars use the lunar cycle to name months, and use the moon to know when to celebrate religious holidays. This is why the religious holidays of Easter, Passover and Ramadan are on different solar days every year - because the moon's orbit doesn't follow the solar calendar.

Until the advent of the printing press, calendars had to be laboriously drawn or painted or sculpted by hand - so calendars were quite limited. This changed in the 15th century, when printers started to print calendars and almanacs, which were snatched up by eager purchasers.  To compete, printers found that they had to create elaborately decorated calendars - forerunners of today's brilliantly colored desk and wall calendars.  Many included pictures of the Zodiac and detailed descriptions of phases of the moon.

Today, thanks to computers and calendar printing services, calendars can be personalized to suit every need and use. People can create calendars filled with their favorite photos, pictures of family members, their company's products, or anything else that can be photographed.  Calendar design templates allow calendar lovers to use pre-established calendar designs, or people can make use of calendar printing services that will design personalized calendars for a low fee.