In one of my medieval lit classes, we read Töres dotter i Wänge, a medieval ballad. I told my professor that it reminded me of Last House on the Left. She said that Last House was based on Virgin Spring, which is based on that ballad.
We watched Virgin Spring in class. She warned us that it would be intense and possibly make some of us uncomfortable and so we didn't have to stay.
I absolutely loved it. And yeah, I was surprised by how graphic it was (not by today's standards of course, but I was definitely surprised).
(Did I already tell you this story? If so, sorry for the repeat!)