Some of us were surprised to learn that only two of Roberto Rosselini's feature length films were "commercially successful"  -- Rome Open City (Roma Citta Apera) (1945) and Il Generale Della Rovere (1959).  We also were surprised (and happy) to learn that Rossellini spent most of his time in bed, and often worked in bed.  At times, visitors who came to his home to discuss business and/or film projects were brought into his bedroom where he sat perched in his bed.  We learned this from the interviews of his daughters Isabella Rosselini and Ingrid Rosselini, which interviews are available on the Criterion Collection DVD of the restored version of Il Generale Della Rovere.  

Il Generale Della Rovere stars actor, film director and Rosselini's friend Vittorio de Sica.  De Sica plays Emanuele Bardone, a con man deep in gambling debt who is forced by a Nazi colonel to impersonate resistance leader Generale Della Rovere for the purpose of infiltrating a prison of political prisoners in Milan during occupation.  The Bardone character is already a skilled actor-impersonator, well-practiced in a scheme of convincing the family members of those detained by the Nazis that he can win the release of their loved ones if they hand over significant sums of cash to be given by him as intermediary to certain Gestapo officers.  He then pockets the cash, gambles the cash, and eventually may hand over some cash to a Gestapo officer, who may or may not (usually not) arrange for the release of the family member.  

Inside prison, at the direction of the Nazi colonel, Bardone transforms himself into Generale Della Rovere, a revered leader of the resistance.  In this acting job, he manages to convince himself that he is worthy, becomes empathetic for his fellow prisoners and allows himself and his fellow prisoners to be commanded by the presence of Generale della Rovere. He is tortured as Generale Della Rovere, then declines to reveal the identify of a fellow prisoner who is a resistance leader.  He then walks amongst his new comrades to be executed.  Bardone is redeemed.  

Sergio Amidei wrote the screenplay for Il Generale Della Rovere, which was based on the novel by Indro Montanelli, which was based on a true story about Giovanni Bertoni.  (Amidei also wrote the screenplay for Rome Open City.)  Real archive footage of Milan during the war, particularly footage of bodies being pulled from bombed out buildings, is incorporated into Il Generale Della Rovere.  

By the way, in 2003, a 1,000 pound unexploded bomb was found during an excavation of a building in Milan, forcing the evacuation of 55,000 people.  It was dropped by the Allies during WWII.  The unexploded bomb was reported to be "in perfect condition."  BBC story HERE.