In Verdi's mind, he had the perfect subject, to be based on the novel "L'assedio di Firenze" ("The Siege of Florence") by Francesco Domenico Guerrazzi, which glorified the life of the 16th Century Florentine soldier Francesco Ferruccio. This new subject was also a patriotic piece: Verdi had taken to heart the admonitions of the poet Giuseppe Giusti, who had pleaded with him after "Macbeth" and after Milan's political turmoil of March 1848 and its aftermath to "do what you can to nourish the [sorrow of the Italian people], to strengthen it, and direct it to its goal".