Cool topic! There is a lot of evidence to support the notion that entheogens(very likely) inform most poetry, myth and religious metaphor. See, Michael Hoffman's>>egodeath.com<< site.

Like many theories regarding human antiquity, "irrefutable" evidence is paltry. However if one investigates the ample data with a psychedelically informed open mind, a rich and "accurate" appreciation of the DEEP relation betwixt entheogens("mixed wine") and religio/spiritual narrative develops.

This is not unique to Greco-Roman/Judeo-Christian(Western) myth and metaphor but is richly evidenced in-the likely ahistorical-biblical mysticism, old and new testament.

Once the enthogen engendered mystical mindstate is recognized as ubiquitous and archetypal in pre-modern human religio/spiritual thought, this probable, foundational aspect of plant entheogens is readily "recognized".

Peace