Trivia: Director William Peter Blatty wanted to title the film "Legion" after his novel the script was based on, while the studio (understandably) wanted to call it "The Exorcist III" for brand-recognition reasons. Blatty absolutely hated "Exorcist II: The Heretic" and felt that the title "The Exorcist III" would suggest this movie followed that one, so he countered by suggesting they title the film "The Exorcist 1990." The studio eventually won out and went with "The Exorcist III."
Trivia: Richard Gere and Andy Garcia did not get along during the filming, and much of their fighting in the elevator sequence is real.