In order to gain the title of Duke of Milan, Filippo has married the former Duke's wife, Beatrice. Filippo is distraught, however, because he is really in love with Agnese. Agnese, meanwhile, is in love with the Lord of Ventimiglia, Orombello; who is in love with Beatrice. Out of jealousy, Agnese arranges that Filippo should catch his wife in a compromising position with Orombello. Thinking falsely that Beatrice and Orombello had been lovers, Filippo sentences Beatrice to death.