When they first started using time-keeping methods what time did they know to start with?

Question

If a sundial was used how did they know what time to call it. did they start with 1:00 if so when did they think to use 12:00 since now we figure 12:00 starts am and pm

Answer 1

Let me know when u know

Answer 2

The study of time and keeping time is quite ancient and all based around mathematics.  It started further back than even 4500 B.C.E.  and was used for keeping moon cycles straight so that they could keep track of when to plant crops.  

The Egyptians were instrumental in getting us to our modern calendar.  They based their calendar year around the flooding of the Nile, very important for them to know this so people could get moved out of the way.  They came up with our current calendar of 365 days in a year.  Although they later discovered a more accurate reading was 364 1/4 days.  We don't do this in our modern time, we simply add a day every 4 years and thus have Leap year.  They figured all of this out around 3000 B.C.E.  or so.

Now I won't get into days and years, it's rather complicated and would take too long to explain.  So I'll skip right to the single day and the hours within.

Early man needed a way to measure units of time, and not surprisingly the sun was used.  The sun dial was first used in about 3500 B.C.E and was called the gnomon.  It was just a vertical stick or rod whose shadow indicated the time of the day.  Now of course the problem with every sun dial is that the suns path changes slightly every day through out the year.   So the sun dial has to be set to a very precise angle so that it will register roughly the correct time.  This took quite a while, and the romans perfected it around 300 B.C.E.

Now sundials obviously only can tell time during the daylight hours.  It is instrumental that the Romans and the Greeks were the people to come up with the concept of a 24 hours period, though not very surprising.  They lived on the equator where the number of sunlight hours and dark hours does not vary considerably between summer and winter.  On average they had around 12 hours of daylight and around 12 hours of dark.   What is remarkable is that we have never strayed from the ancient Greek and Roman methods of counting hours and keeping time.  They did not start it with 1 o'clock, they based everything off of the base 12 latin system.  12 o'clock was when the sun was at its zenith.  Even way back in the B.C.E> times they had numbers and it was logical that the numbers on a sun-dial should go from the first to the last.  The history beyond the concept of time really gets interesting when they start philosophising about it, especially with Aristotle and Plato,  but as far as how we got our 24 hour day, it was because brilliant societies living on the equator created it way back in 3000 B.C.E. and it has not changed since then.

Hope this helps some.