Included in the acting cast is Gianfranco Bellini as the narrator, who has voice-dubbed several American films for the Italian cinema. Monks from the Nocere Inferiore Monastery played the roles of St. Francis and the friars. Playing the role of St. Francis is a Franciscan brother who is not credited, Brother Nazario Gerardi. The only professional actor in the film is the prominent Aldo Fabrizi, who had worked with Rossellini before, notably in the neorealistic film "Rome, Open City". The film garnered international acclaim for Fabrizi. He began his film career scene in 1942, and is noted for both writing and directing his own vehicles. In this film, Fabrizi plays the role of Nicolaio, the tyrant of Viterbo.