What Year Did The Calendar Start. With that convention september is the 7th month and starts in sept for 7 october is the 8th month and. In 2013, british archaeologists discovered what they consider the world’s oldest calendar, dating back to around 8000 bce.
Evidence shows that dates from ancient civilizations like the sumerians, egyptians, and mayans used calendars. But the julian calendar was actually very close to being right.