Actor Paolo Stoppa, who plays Pope Pio VII in this movie, has the unusual record of having played the role of a Pope no less than four times in his career, including Saint Peter in Nerone (1977), Alexander III in Becket, o Favorito do Rei (1964) and an unnamed Pope in Jus primae noctis (1972).
The most famous gag in the movie is probably the one where the Marquis Del Grillo (Alberto Sordi) says: "Mi dispiace ma io so' io, e voi non siete un ca**o" ("Sorry, but I am myself, and you are nobodies"). This sentence is taken from the Roman sonet Li soprani der monno vecchio (1831) by Giuseppe Gioachino Belli, cited also in the movie Remo e Romolo - Storia di due figli di una lupa (1976).
A sentence from this movie is written on Alberto Sordi's grave.
Actor Giorgio Gobbi, who played marquis' friend Ricciotto, stated in an interview that Alberto Sordi initially didn't want him for the role due to his young age. At the end, director Mario Monicelli decided to go ahead with him and Gobbi and Sordi got along very well together and had a lot of fun while filming.
The scene of the identity exchange between the nobleman and the charcoal burner is inspired by several novels, like One Thousand and One Nights and William Shakespeare's The Taming of the Shrew, but also the narration Novella del Grasso legnaiuolo, which tells of a joke by Italian architect Filippo Brunelleschi.