The article first shows how the socialist press considered Italian and foreign operas, taking Verdi as the father of the nation. The opposition to Verdi is represented by Wagner, whom Italian socialists call a revolutionary and « communist » artist. Then the article relates music to militant and daily practices of leaders, officials and activists, and looks at the place of music in party festivals. Finally, it analyses the function of political songs written by socialist intellectuals, their diffusion within the party and in Italian society, and their use as an identifying and political weapon against the enemies.