Other examples from the end of the eighteenth and beginning of the nineteenth century, the period when rescue opera flourished, are Nicolas Dalayrac's "Camille ou Le souterrain" (1791), Jean-François Le Sueur's "La caverne" (1793), and Cherubini's "Les deux journées" (1800). While the rescue opera was primarily a French genre, the two best-known operas in the genre are not French. Ludwig van Beethoven's "Fidelio" is by far the most famous example today, and was also influenced by the German "Singspiel". A work which is similar to "Fidelio" is Rossini's "Torvaldo e Dorliska" of 1815. Bedřich Smetana's "Dalibor" (1868), which contains no spoken dialogue and which bears marks of Wagnerian influence, has nonetheless been called a rescue opera, in part because of its political themes. Rescue opera was primarily a product of the French Revolution. The social changes of the period meant that opera must now appeal to the masses, and post-aristocratic, patriotic, idealistic themes—such as resistance to oppression, secularism, the political power of individuals and of people working together, and fundamental changes to the status quo—were popular. The Terror influenced stories of fear and imprisonment; a number of plots, including that of "Fidelio" and other operas based on the same libretto as well as that of "Les deux journées", were taken from real life. Stylistically, rescue opera was an outgrowth of the "opéra comique", a bourgeois genre. Like "opéras comiques", rescue operas contained spoken dialogue, popular musical idioms, and bourgeois characters. Works with libretti by Michel-Jean Sedaine were particularly influential. The influx of suspenseful or tragic subjects into "opéra comique" caused confusion in a system where tragedy was associated with through-composed scores and comedy with dialogue, precipitating a shift of musical theatre genres that paralleled the political shift which empowered the middle-class. Carl Dahlhaus writes, "No longer did the bourgeoisie function in comic casts merely as the butt of jokes; it demanded, and received, its part in the dignity of tragedy." Some scholars describe the plots as featuring a "deus ex machina" like the ones present in opera seria plots, though the resolution still bore a closer resemblance to the endings of domestic comedies.