The romantic opera 'Fidelio' has as an exterior subject a love story but its basic message is longing for freedom, shaking off of slavery and generally, the themes with which nowadays-social reality deals with. The source for Beethoven is the play 'Leonore' of the French dramatist Jean -Nicolas Bouilly, which most probably is based on a real event. From the French original remains almost nothing, apart from the basic idea of release from the oppression, the idea, which from the outset has inspired Beethoven. Fidelio is in fact a young noble woman, Leonora, disguised in man, searches his husband Florestan, who, as she believes, the group of his political enemies has imprisoned. The music in Fidelio, does not follow the rules of Opera and it is voluntarily restrained, so as to not disrupt the framework of the play. The musical expression does not serve aesthetic rules but a great idea. When though a dramatic scene inspires him, Beethoven puts all his persuasion and his power to music. For example the big Aria of Leonora, the choro of the prisoners and the scene in the basement.