[carlmr]

Alcohol consumption (and production) by monks and priests is well documented. Also they hotbox the whole church a few times a year, maybe the mix used to be more interesting, especially when you have a monastery with a good medicinal garden.

[t_mann]

You're talking about Christian traditions, though. This is specifically about pre-Christian cults.

[LargoLasskhyfv]

There is (frank)inscense. Which has been used since long before them. Just search for "psychoactive inscense"