A Complete History of Calendars

When you take a look at that branded calendar on the office wall or desk, you probably don’t picture it as a historical artefact. It’s unlikely that you’d consider its social significance as you jotted down your notes and dates on its front. It’s a crying shame, because calendars are one of the most important developments in human history.

Where would we be without our rigid structure of weeks and months? How could you ever visualise the months and years passing if you didn’t have a calendar? They might seem like a pretty minor part of everyday life, but you’d better believe that life would be a whole lot harder without them. The history of the calendar spans several thousand years – it’s an age old tale of innovation and invention, precision and perseverance.

In the earliest recorded years, human beings calculated the passage of time by observing periods of light and darkness. We may have invented the fittings and trappings that frame the concept of time, but we obviously didn’t create it – the solar day is a natural calendar. It is also the oldest type of calendar, followed closely by the practice of counting days in a predefined cycle. There was very little control and almost no accuracy with the earliest forms of calendar. You could count the days leading up to an event and you could count the days following an event, but you couldn’t use them in conjunction with the seasons.

This was a huge flaw for arbitrary calendars – farmers could not use them to identify the best planting and sowing times. It was at this point that human beings began to design and create sundials. In 45BC, Julius Caesar invented the rather aptly named Julian calendar. Unlike earlier Roman calendars, this calendar was made up of twelve months. A lot of the months were shorter than the ones that we’re used to now, and there were only three hundred and fifty five days in the year. The Julian year was a departure from earlier examples, which all tended to officially start on 31st March, say the experts at InfoPlease.com.

Under Caesar’s reign, the length of a week was reduced by one day and transformed into the seven day week that we have now. He also introduced the month of February and the leap year rule – this rule stated that all leap years can be evenly divided by four. For a long time, the Roman Church and the Irish Church argued about the calculation of Easter. Due to the immense size and influence of the Roman Empire, it was decided that Easter Day should fall on the first Sunday after the paschal full moon. This phrase AD (anno domini) dates back to this period and this particular decision, says TimeCenter.com journalist Niclas Marie.

In 1582, Pope Gregory XIII announced plans to change the Julian calendar. He believed that it was no longer accurate enough, and he wanted to create a calendar that was more precise. The Gregorian calendar is a theoretical calendar, based on very precise calculations involving vernal equinoxes. This is now a globally recognised form of calendar, and it has been since the early part of the twentieth century. Today, it is the most widely used calendar in the world. The next time that you take a look at that calendar on the office wall or desk, just remind yourself that it didn’t get there by accident.