Originally Posted by jay norem
Pythagoras, around 400 B.C.
Very true. One person, one simple discovery that led to Western melodic organization. He found that if you cut the vibrating length of string in half, the sound waves doubled in frequency, the basis for the octave. Not a huge mystery and someone was bound to have discovered it eventually (maybe Eastern musicians did and thought little of it) but that was clearly a defining moment.