Spontini carried further the seriousness in opera established by Gluck. Gluck's reforms influenced Mozart, but until Berlioz and Wagner, he did not have a true successor. The first rescue opera staged in Vienna was Lodoiska in 1802. In rescue operas, the principal character is in prison as a result of a political act. The rescue should be achieved by ordinary human characters in a realistic way.
Themes deal with survival rather than death.
The rescue opera is classified as a Romantic operatic genre rather than Classical. This tradition was somehow restricted to Paris perhaps because the visual spectacle was so important in French opera but not so prominent in Italy. The main opera genres in the eighteenth century were the Italian opera seria and opera buffa and the French tragedie-lyrique and opera comique. The main sources of Romantic opera lay in the comic opera traditions. Italian opera in the nineteenth century remained a 'number opera', and division of the drama into clear-cut forms continued.