Seikilos epitaph
The Seikilos epitaph is the oldest surviving complete musical composition, including musical notation, from anywhere in the world. The epitaph has been variously dated, but seems to be either from the 1st or the 2nd century AD. The song, the melody of which is recorded, alongside its lyrics, in the ancient Greek musical notation, was found engraved on a tombstone (a stele) from the Hellenistic town Tralles near present-day Aydın, Turkey, not far from Ephesus. It is a Hellenistic Ionic song in either the Phrygian octave species or Iastian tonos. While older music with notation exists (for example the Hurrian songs), all of it is in fragments; the Seikilos epitaph is unique in that it is a complete, though short, composition.
Music of Mesopotamia
Mesopotamian music had a system that introduced rigidity in the music, preventing the melody from developing into chaos. Until recently no form of musical notation had been known, however there is a cuneiform tablet containing a hymn and what has been translated as musical instructions for a performer, making this tablet the oldest known musical notation. There were strict instructions for how to perform music, similar to chord progression today. These instructions also seem to point to a strong desire for musicians to play in tune, with steps in performing requiring frequent attempts to tune the instruments.