Roberto Rossellini and Sergio Amidei took their inspiration from two real-life people, Pina from Teresa Gullace, a Roman woman killed on a street on 3 March 1944, and Manfredi from Cesare Negarville, a partisan that Amidei had hidden at his home during the War.
Before starting filming, Roberto Rossellini had signed a contract for distribution with Artisti Associati. However, the firm would not honor its commitments, arguing that the film was more a report than a fiction film. Rosselini then managed to sell his rights to Minerva Films, which finally released it.
The trivia item below may give away important plot points.
Don Pietro Pellegrini's appeal to the God to forgive his executioners for what they are going to do, is a reference to what Jesus said to the God before he was crucified: "Father, forgive them, for they do not know what they are doing" (Luke 23:34).