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.
Part (music)
The historical development of polyphony and part-writing is a central thread through European music history. The earliest notated pieces of music in Europe were gregorian chant melodies. It appears that the "Codex Calixtinus" (12th century) contains the earliest extant decipherable part music. Many histories of music trace the development of new rules for dissonances, and shifting stylistic possibilities for relationships between parts.