I Tre volti della paura or Black Sabbath (1963) is a Italian gothic horror movie directed by Mario Bava. Boris Karloff has a role in it.
A trilogy of three horror stories. "The Drop of Water" concerns a nurse who steals a ring off a dead spiritualist, only to have the corpse seek revenge. "The Telephone" features a prostitute who is terrorized by phone calls from a dead client. "The Wurdalak" stars Boris Karloff as a vampire who feeds on the blood of his loved ones.
Link to "Tre volti della paura" on IMDB.com
In 1969, a heavy blues-rock band named Earth decided to change their name and agreed that the title of this movie would be a nice fit for their burgeoning "heavy metal" sound.
Link to "Black Sabbath" on Wikipedia.org