Det Sjunde Inseglet is the (Swedish) original title of the movie that is known as The Seventh Seal in English.
It was made by Ingmar Bergman in 1957 after a play with the same name and author and is about a knight returning to his black plague-ravished home land after a crusade. He plays chess with death and recites long philosophical monologues. As the writeup in The Seventh Seal notes, it's existentialist porn and maybe the best movie ever made.