 Complete the following phrase:  In Verdis mind, he had the perfect subject, to be based on the novel Lassedio 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 Milans 