What is the title of the film showcased in 1997 Mel Gibson film "Conspiracy Theory"?

In a scene in the 1997 film, Conspiracy Theory, Mel Gibson's character is attempting to evade government agents by hiding in a theater. As he enters the theater, a film is already being played. I believe it's black and white, and it depicts a man on a horse, slowly being ridden through a chapel. what film is this?