The endurance of the horror genre throughout the last century, from the silent era to today, owes more than a little to it's relation to some basic theological aspects: we are all sinners and unless we change our ways, we will be punished. Even someone like myself who grew up in a secular household knew enough about the proposition of going to hell to be scared into being a good boy.
It is obvious why religious themes seep into many horror classics (Frankenstein, Rosemary's Baby, The Omen, et cetera) because what is playing god or false prophetizing but the ultimate sin against man and who is Satan if not the ultimate villain?
Of all the movies to delve into these themes of the good versus evil principle of the majority of your, let's say, more popular religions, none is quite as effective as The Exorcist. It's still hard to imagine that director William Friedkin and writer William Peter Blatty got away with so much here both thematically and visually, it's success proving just how tumultous and divisive the 70's were in America, specifically 1973-74, the height of the Watergate scandal and the continuing Vietnam War.
So how did Warner Brothers try to sell what would become a controversial smash hit? Hint: Not so much emphasis on crucifix masturbation.
Here's the trailer:
The Exorcist opened December 26th, 1973. Happy Belated birthday, Jesus!