A calendar is a system that we use to count, define and keep track of time. We calculate days, months and years with the use of a calendar.

Was the Coligny calendar solar or lunar?

The calendar that we use in modern days, and that is used in most parts of the world, is the Gregorian calendar. It is a solar calendar; this means that it is fundamentally guided and based on the Earth’s movement around the Sun.

But, in addition to solar calendars, we also have the existence of lunar calendars. This type of calendar follows the amount of time that it takes for the Moon to complete its four orbiting phases around the Earth, and the result of that is called a lunar month.

Even a combination of both types of calculation exists as well in some kinds of calendars.

So, essentially, a calendar helps us coordinate time. Our use of the Gregorian calendar tells us that it takes the Earth 365 days to make a whole circle around the Sun.

There are twelve “lunar months” in one solar year, and this is called a lunar year. This means that in the essence of quantity; both years share 12 months. But, Lunar years do not coincide with solar years. A lunar year has a total of 354 days; this is the reason why every certain time there are thirteen lunar months in one year.

The Coligny calendar, is a lunisolar calendar, this means it combines Moon phases and the time of a solar year as well.

This calendar was found in Coligny, Ain, France in 1897. It is a big bronze tablet that was originally found broken into 73 pieces. It is believed to have been prohibited by the Romans during the Roman Empire, because at the time, Julius Caesar was making imperative the use of his calendar; the Julian calendar.

The Coligny calendar was part of the beliefs, culture and traditions of the Gaulic groups. These groups were integrated by Celtic people of an educated and professional class of Gaul, Britain and Ireland.

Now, let’s compare the Gregorian calendar to this ancient Coligny calendar.

The calendar that we use today (Gregorian) is summed up by 12 months, starting with January and ending with December. Each month has either 30 or 31 days, except for February, which has 28 days and only every 4 years contains 29 days.

Again, this calculation of time is based on the Earth’s movement around the Sun.

What makes the Gregorian different from the Coligny calendar?

Now, the Coligny calendar has a total of 12 months as well, beginning with Samonios and ending with Cantios, and each month had 29 or 30 days. And every 2.5 years, there was an extra month that was added; Sonnocingos, which was the intercalary month. This means it could be inserted before Samonios or between Cutios and Giamonios.

The Coligny calendar was a system of 30 years, divided into 12 months and the extra month number 13 every 2.5 years. Then each month was divided into halves. The first half would be made out of 15 days, and the second half would contain 14 or 15 days. At this point it was following the phases of the moon, which means that every center of the month we would have a full moon during that night.

The Coligny calendar is believed to be no longer used in the present, but there are still cultures and religions that base their calculation of time on a lunar or a lunisolar calendar.

Even though the use of the Coligny calendar was forbidden during Julius Caesar’s Roman Empire, the discovery of this ancient tablet suggests that Celtic tribes were trying to preserve their ideologies over the ones of Julius, even in the middle of difficult times of invasion and conquest.