From asking How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days? I'm now wondering how cultures like Ancient Egypt, with their 12-month, 30 days per month solar calendar year (360 days), plus 5 or 6 feast holidays to make it 365 or 366 (leap year) days per year.

How did they justify having "random extra days" in their calendar? How did other cultures justify this similar thing in their calendars?

  • The basic justification is that if they didn't, then the months would drift through the seasons, which makes agricultural planning difficult.
    – OrangeDog
    Commented Apr 29 at 21:55

1 Answer 1


In Egypt, the myth was that Ra had cursed Nut to not give birth any day of the year, then 360 days. She went to Thoth for help. Thoth gambled with Khonsu, the moon god, for his moonlight, and got enough that Khonsu had to wax and wane because of how much light he had gambled away, and Thoth had enough to make five more days, so that Nut could give birth. Thus, they were odd days, not falling in proper sequence.

This was rare. Most cultures simply treated the year as 365 days because that's what it was. Or whatever quantity they thought it was according to their best astronomy, followed by tinkering as needed.

  • Source for "this was rare"? Most ancient cultures were trying to fit twelve lunar months into a solar year, so ended up with extra non-month days, or years with extra months in them. See the Roman, Hebrew, Chinese, Hindu, and Salish calendars.
    – OrangeDog
    Commented Apr 29 at 21:52
  • Exactly. Extra months, not extra non-month days. Putting in non-month days moves you further and further from the moon.
    – Mary
    Commented Apr 29 at 22:53
  • the Roman and Salish calendars also have non-month days.
    – OrangeDog
    Commented Apr 30 at 8:28
  • The Roman one went for the intercalary month, except for political reasons they frequently skipped it, which is why Julius Caesar did the big reform. The winter not divided into months was legendary.
    – Mary
    Commented Apr 30 at 22:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.