"fidelio" is an example of a “rescue opera”, a type of opera which was popular at the time. the hero (or heroine) has to fight against cruel people in order to rescue a lover. it was written at the time of the french revolution. at this time, ideas about freedom and peace were being talked about by everyone, and this led to wars all over europe. the famous prisoners’ chorus is a song for freedom, just like the last movement of his ninth symphony.