Written music as we know it only goes back a few centuries. I think early forms may go back 1000 years.

Archaeologists found a Sumerian clay tablet from 3400 years ago that seems to represent music and someone has transcribed it. They were ahead of their time as people thought that harmony came much later. I don't think this should be a surprise as people were just as clever back then and they had plenty of time to develop advanced music. That knowledge may well have been lost until much more recently.

http://www.openculture.com/2014/07/the-oldest-song-in-the-world.html