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Who Invented The Calendar?

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It is hard to determine just who invented the calendar. We can however determine just who influenced the calendar we use today and some of the major changes that were involved with the development of the calendar. There are several calendars that are used today. However there is one that is used more than others. From the moon to the seasons, the length of the days to the length of the nights, calendars have been developed from all types of sources. Read on to learn more about the invention of the Calendar and possibly just where it came from.

Pope Gregory XIIIPope Gregory XIII introduced the Gregorian calendar that we use today. Painting: Lavinia Fontana.

Lunar Calendar

The lunar calendar was used by the Babylonians, Jews, Greeks and the Chinese. The calendar was a 19 year period, there were 7 of those years that actually had 13 months instead of 12. This type of calendar was used also by the Arabs; it was Muhammad that restricted the 13 months. He preferred the 12 month calendar, so because of him, the Islamic calendar has around 354 days; this resulted in the Islamic religious festivals to cycle through each season.

Egyptian Calendar

The Egyptians had a calendar that had a total of 12 months that consisted of 30 days. Around 4000 BC, the Egyptians added 5 extra days. This was to help align with the solar year. These yearly 5 extra days had eventually turned into a festival. The belief was that it was unlucky to work doing these 5 days.

Roman (Julian) Calendar

The Romans had a complicated calendar that consisted of either 29 days in a month or 31 days. They decided on amounts due to their superstitions of numbers being bad luck. It was Julius Caesar, with the help of an astronomer adviser that created a new calendar. It was in 46 BC that by imperial decree the year was 445 days long.

Gregorian calendar, the modern day calender

This corrected the calendar with the proper seasons. With the calculations of the solar year being 365 days and 6 hours in length, the months were given either 30 or 31 days and every forth year had an extra day to make up for the 6 extra hours a year. It was also Caesar that decided the year was going to begin on January 1st instead of in March on the equinox. In 1582, the world adopted the Gregorian calendar, thus replacing all other previously used calendar system. It was named after the man who introduced it, Pope Gregory XIII.

More on calendars: Facts about calendars.