3.2 The julian and gregorian calendars

The Gregorian calendar system is sometimes called the "Christian calendar", because it starts counting the years from the birth of Christ. But its origins are much more complicated. We can trace it back to the Julian calendar , which was a reform of an old Roman calendar system by Julius Caesar .

Of course, Julius Caesar lived before Christ, so he could not really use that as his starting point. Instead, he counted the years since the founding of the city of Rome in the year 753 BCE. Only around the sixth century did the practice of dating time from the birth of Christ start to become common, and counting backwards from that point (the years BCE) did not really catch on until the seventeenth century.

Every calendar has a starting point, and the years before that starting point count backwards! The Jewish philosopher Philo of Alexandria was born in 15 BCE. In what year would he be celebrating his twelfth birthday? 3BCE

You know how the birth and death dates of a person are indicated? You will read in history books about Mr BB Brown (1910–1969), so Mr Brown lived for 59 years. Let's return to Philo. He was born in 15 BCE and died 65 years later. How would you write his name together with those two dates? That would be Philo (15 BCE-50 CE)

The Julian calendar worked well for a long time, but every 128 years, it gained one day, and by the 1580s the calendar was 10 days ahead of the real time. In 1582, Pope Gregory XII therefore instituted calendar reform by simply dropping 10 days from the calendar!

A lot of people were furious with Pope Gregory. They believed that by changing the calendar, he had shortened their lives by ten days!

He ensured that the error should not happen again by making subtle changes in the number of leap years. Pope Gregory's system has been adjusted since then, but it is basically the system still in use today and is called the Gregorian calendar system in his honour.

The Orthodox Church continues to this day to use the Julian calendar to calculate the dates for its festivals. The Orthodox Easter and Christmas holidays therefore fall on different days than those celebrated by Catholic and Protestant Christians.