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.
Old Hall Manuscript
The Old Hall Manuscript (British Library, Additional MS 57950) is the largest, most complete, and most significant source of English sacred music of the late 14th and early 15th centuries, and as such represents the best source for late Medieval English music. The manuscript somehow survived the Reformation, and formerly belonged to St. Edmund's College, a Roman Catholic school located at Old Hall Green (hence its name) in Hertfordshire. It was sold to the British Library after an auction at Sotheby's in 1973.