If I understand correctly, there where 36 clay tablets with hymns on them found at a dig, and this just happens to be the sixth one to be catalogued.

Number 5 was a mambo

There are hymns 1-5 (tho this is just order of discovery / classification), however the rest is too fragmentary and incomplete to reconstruct anything.

The title is a bit misleading this is the world’s oldest know complete (kinda) piece. As in something we can reconstruct and play.

Though even that’s hedging a lot as the original notation only explains string positions (which strings are manipulated). Scale, rhythm, technique, etc… are all missing, so there are wild divergences from the base reconstruction (samurai guitarist has a video on it).

Or even 6 if they were written by computer scientists counting from 0.