The calendar we use today has been developing for millenia, since the days of ancient Egypt. The best minds of countless generations have worked to make the calendar as accurate as possible, but even today the calendar grows more inaccurate with each passing year.
Measuring the Passing of the Seasons in Ancient Egypt
The Nile was the source of civilization in ancient Egypt.
At the edge of the Sahara desert, without the annual
flooding of the Nile agriculture would have been near impossible
and the cities of Egypt
would have withered away.
In order to better keep track of the flooding of the Nile,
the first calendars were developed in Egypt.
These calendars were based on the passing of the seasons and thus the length of
time it takes for the Earth to revolve around the Sun. For this reason we call
this type of calendar a solar calendar.
Egypt was
the only culture of its day to develop a purely solar calendar. Other
developing civilizations used the moon as the basis of its calendar
development, with the month as its primary measuring instrument, although they
did make some changes to make months match up with the solar year. Not all did,
in fact many calendars today, most notably the Islamic calendar, follow the
lunar cycle and do not match up to the solar year.
The moon was not important to the ancient Egyptians. The accurate prediction
of the flooding of the Nile was their primary concern,
and thus they developed a 365 day year.