Tosca's première in Rome in January 1900 was nearly disrupted by a terrorist threat to blow up Italy's King Umberto. Victorien Sardou had written the melodrama for the great actress Sarah Bernhardt. Giacomo Puccini's popular opera is a tale of sadism and brutality, torture, attempted rape, murder, an execution and two suicides. 'Realism' was in vogue: Mascagni's Cavalleria rusticana had been a gre...