This important XIX century work about the medieval history of Sicily, starting from the events of the Sicily Kingdom after the death of Frederick II, details the "bad signoria" of Angiò, the growing vein of Sicilian sentiment against the oppressor, the explosion of popular revolt, the foundation of the "Communitas Siciliae" and its change then in that new monarchy that for nearly twenty years sustained a victorious war against Rome and Angiò, in an interweaving of power relations that had profound reflections on the political system of Christianity.