What happened in year 0 zero

Where does our calendar come from and who started counting the years?

For us, the counting of the year begins with the birth of Christ. Because that was a little over two thousand years ago in year zero. There is a time calculation AFTER the birth of Christ (everything that was and will be from the year zero to today), and there is a time calculation BEFORE the birth of Christ (everything that was UP to the year zero). But how come? Why is the birth of Jesus Christ, of all things, the starting point of our calendar?

Our calendar goes to the roman emperor Gaius Julius Caesar back. He introduced the Julian calendar in 46 BC.

From observations of the heavenly bodies it was known that a year is 365 days and 6 hours long. That is how long it takes the earth to orbit the sun. However, there were still different starting points for the Roman calendar.

Christianity gained more and more influence in the Roman Empire. In the 6th century, the monk Dionysius Exiguus suggested that the calendar should start with the birth of Jesus Christ. When that was, however, was no longer exactly known. It is now assumed that the birth of Christ took place 5 to 7 years before our calendar. Nevertheless, this event (the birth of Christ) was now taken as the starting point for the calculation of time.

A few centuries later - namely in the 16th - Pope Gregory the thirteenth made some changes to the Julian calendar. And this - called since the Gregorian calendar - is still valid today.