"The Flowers of St. Francis" was edited for its 1952 US release, with Rossellini's chapter-like inter titles and a couple of scenes removed from the original Italian version. They have been reintroduced in the Criterion and in the Masters of Cinema edition.
Roberto Rossellini and 'Ingrid Bergman' were involved in an highly publicized and strongly condemned love affair during the making of this film and Bergman was pregnant with Rosselini's child while married to another man. These circumstances in Rosselini's personal life made the shoot more difficult.
Roberto Rossellini was one of a group of pioneering film makers of the neo-realist era. Rather than shooting on stage, they shot on locations and quite often used non professional actors. Most of the performers in the film, with exception of Aldo Fabrizi, are real Franciscian monks.
The filmmakers wanted to donate something to the monks who acted in the film since they refused payment. According to Rossellini's daughter, he expected them to ask that the donation be something charitable - setting up a soup kitchen or the like. Instead, the monks surprised everyone by asking for fireworks. Rossellini saw to it that the town had an enormous, elaborate fireworks display that was the talk of the region for years.
The one who was called "Jester of the Lord" was Brother Juniper, Francis's disciple, not Francis himself as the Italian title erroneously indicates.
The roles of St. Francis and his disciples were played by monks from the Nocere Inferiore monastery.
The screenplay takes its inspiration from the 14th Century legends "Fioretti di San Francesco" and "La Vita di Frate Ginepro".