3Based on the play by Schiller about tragic love and intrigue at the court of Philip II of Spain, Don Carlos is among the most complex and challenging of Verdi's works. The composer revised the opera twice in the 20 years following its 1867 debut at the Paris Op ra, incorporating into it the musical ideas that later culminated in such masterpieces as Otello and Falstaff. For that reason Don Carlos is much studied by students and performers, who will welcome this new edition of the final version, reprinted from the authoritative G. Ricordi edition. Note. Credits and Characters. Annotated Contents. Instrumentation.