What historical event would mark year 0 on a secular calendar?
What would be the event that marked the first year of a secular calendar, that is, an event in no way related to religion. Keep in mind practicality, for the simple reason that a year will some 11 digits that is based on the formation of Earth, or the Big Bang, would be very tedious, and not necessary.
This question is in the General Section. Responses must be helpful and on-topic.