The Elixirs of the Devil (1976)

The Capuchin monk Medardus is appointed curator of the relics in the Bamberg monastery. There he discovers a legacy of St. Antonius: a mysterious bottle with a liquid, supposedly the devil's elixir. Medardus succumbed to the temptation to cost - whereupon the dark sides of his soul take possession of him. When the young baroness Aurelie falls in love with Medardus and the prior learns of the romance that is going on, he sends the monk on a trip to Rome to the Pope. But the way there becomes a hell trip, because his dark alter ego follows Medardus like a shadow, and soon terrible crimes will be charged to him.