Twice a year, a day comes along where the length of daylight equals the length of darkness. Today we call that day the “equinox”. We recognize the vernal equinox as the first day of spring and the autumnal equinox as the first day of fall. These two days have always been important indicators for man since even ancient times.
Before Europeans came to America, Native Americans did not have bankers, insurance agents, or real estate agents so where did they get their calendars? How did they know when spring or fall arrived? They had someone more important to them than our bankers or agents are to us, they had astronomers.