 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.