I've read a lot about Greek and ancient music. The history books say this music was only monophonic and we know only from iconical research (studying pictures from ancient times) of the practice of the ancient period.
My assumption is that the music was rarely notated and if it was, then only monophonically, but when it was played it must have been polyphonic.
Is there any evidence in historical literature or are there other theories of other researchers that support my hypothesis?
Edit:
I assume that there were more different instruments playing at once and not unisono. e.g. Nebukadnezar or the battle of Jericho. Maybe I have to overthink my understanding of polyphony. I thought monophonic implies all instrument or voicing are playing the same tune ... what in my imagination was almost impossible. I would imagine that one or more singer have been accompanied by a harp or a lyra in chords (eventually fourths and not triads and also there could have been happenings with improvisation in a poly rhythmic and hetero-phonic art and kind.