According to Professor Birgitta Steene, the title is drawn from Swedish folklore, where the "hour of the wolf" refers to the period from 3 a.m. to 5 a.m., supposedly when the most deaths and births occur. Folklorist Bengt af Klintberg recalled that in 1964, Bergman tasked theatre manager Niklas Brunius to research legend about the hour, and Brunius asked Klintberg about it; Klintberg found the term had no roots in Swedish folklore, though there was a "ghost hour" between midnight and 1 a.m. Bergman claimed he first came across the term "hour of the wolf" in a Latin source, though he did not identify the source and may have coined the term himself. He later said that at the time of the story's conception, he was experiencing his own "hour of the wolf", and was "freed" from it upon the production's completion.