People across the world follow the Gregorian calendar.
The world converted to the Gregorian calendar in 1752. Otherwise different people around the world followed different calendars. Infact people who do agriculture and farming, still use a combination of solar and lunar calendars.
Who came up with the 12 month calendar?
The 12 months in the calendar, as we know them today, were first introduced by Julius Caesar, in the year 45 BC, on 1st January.
How many months were in the original calendar?
The calendar used previously consisted of 10 months. But it couldn’t account for the cyclic revolution of the earth around the sun, which takes exactly 365.2422 days.
The 10 month calendar
The previous Roman calendar, began the year in March and ended it in December. It had been in use from 753 BC, by Romulus, the legendary first king of Rome.
This calendar was later modified because it accounted for only 304 days in a year.
Who started the leap year?
The second king of Rome, Numa Pompilius added two months at the end of the calendar, Ianuarius and Februarius, to account for the missing days. He also introduced an intercalary month that occured after Februarius in certain years. These years became known as leap years. In addition, he deleted one day from all the months that had 30 days, so that they had 29 days instead.
Around for 700 years!
This resulted in a total of 355 days in a common year and 377 days in a leap year. The leap years were declared at the whim of the king. Although unstable, the calendar was in use for 700 years.
But it got very confusing because seasons and calendars did not match. It played havoc with the farmers.
So Julius Caesar, in 45 BC, under the guidance of his astronomers, decided to alter the calendar and make it more stable. Finally, the seasons had a chance to catch up!
For sixteen centuries!
When did we switch to the Gregorian calendar?
The same calendar had been in use since 1752, when the Gregorian calendar was adopted all over the world, to synchronise it to the English and American Colonies. The world and its boundaries had expanded quite a bit, from Caesar’s times! The Gregorian calendar fixed the Julian calendar error of calculating one revolution of the earth around the sun to take 365.2422 days, into account.
So, there you have it! It was originally Julius Caesar, who initiated the 12 months we have in the calendar today!