The operetta 'Wiener Blut' is set against the Vienna of the early nineteenth century, during the Congress of Vienna. At that time, the Biedermeier city was poised to become a pulsing metropolis, a culturally sophisticated center of a modern empire. At the same time, Wiener Blut is an operetta about Vienna and the waltz Wiener Blut, describes what it is like to have Viennese blood coursing through one's veins. One of the highlights is the (soprano - tenor) duet 'Das eine kann ich nicht verzeih'n' sung by the Count and the Countess Zedlau in the second act.