There was a thread on the question of "pagan music" back in 1998, I believe. (click??)
Actually, scholars have deciphered a Greek "Hymn to the Sun" and "Delphic Hymn". Other scholars claim to have deciphered musical notation from cuneiform texts. This is certainly "pagan" music by any definition.
The tune Nonesuch has long been associated with the words (dating from the English Civil War of the 17th century) "I have of late been in England/where we have seen much sport."