According to his autobiography, Robert Wagner didn't get along at all with Maximilian Schell, who had just won a Best Actor Oscar for his performance in "Judgment at Nuremberg". He found Schell to be "stunningly unprofessional" and "calculatingly rude".
Even though he was keen to work with Sophia Loren, Kirk Douglas turned down the Maximilian Schell role.
This is loosely based on the Krupp family, one of the major German industrialists during the rise of Nazism.
This was not a commercial success, and nearly caused the downfall of the Italian production company, Titanus Films.