While "Angelina", the film in which he appeared as an actor, was being released in theatres, Zeffirelli decided to embrace what would later become his profession, accepting an offer to follow Luchino Visconti to Sicily as an assistant director. The production of "La terra trema" was quite unique: the film was shot in Aci Trezza and featured non-professional actors, who were asked to immerse themselves in their characters to the point of improvising dialogues based on a predetermined storyline.
Visconti's two assistants were Zeffirelli and Francesco Rosi, both with acting experience but newcomers to directing. Zeffirelli was assigned the task of preparing the actors, while Rosi was responsible for ensuring continuity between the different scenes.