The movie was based on the Pentamerone ("The Tale of Tales, or Entertainment for Little Ones"), a collection of fairy tales by 17th century Italian poet and courtier Giambattista Basile.
The scene with the King of Longtrellis fighting the aquatic dragon was supposed to be much more dynamic, but Matteo Garrone had to make some adjustments (for instance, the point of view shot of the King) because the dragon itself (an actual prop and not CGI) broke down while being shown to Garrone's son and his classmates during a break.
When Violet strums her guitar and sings a song, her clothes, hair, guitar and the overall appearance of the scene recreate very closely a famous painting by Jan Vermeer ("The Guitar Player").
'Il Pentamerone' by Giambattista Basile was written in the 17th century and contained fifty Neapolitan tales, linked together by one frame story, in a similar style to the Arabian Nights. This film adapts three of these stories, with elements transplanted from several others.