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.
Dafne
Dafne is the earliest known work that, by modern standards, could be considered an opera. The libretto by Ottavio Rinuccini survives complete; the mostly-lost music was completed by Jacopo Peri, but at least two of the six surviving fragments are by Jacopo Corsi. "Dafne" was first performed during Carnival of 1598 (1597 old style) at the Palazzo Corsi.