Mozart’s opera featuring Don Alfonso and the sisters Fiordiligi and Dorabella is Così fan tutte.
The opera’s full Italian title, Così fan tutte, ossia La scuola degli amanti, is commonly translated as “Thus Do All Women” or “The School for Lovers.” Lorenzo Da Ponte wrote the libretto, making it the third and final collaboration between Da Ponte and Mozart after The Marriage of Figaro and Don Giovanni.
The plot follows a wager proposed by the cynical Don Alfonso. He persuades two young officers, Ferrando and Guglielmo, to disguise themselves and test whether their fiancées remain faithful. The sisters’ emotional reversals give the work its deliberately artificial, comic structure.
Così fan tutte premiered at Vienna’s Burgtheater in 1790. Its title is sometimes misunderstood as a general statement about women; in context, it is a comic phrase spoken within the opera’s plot, not a neutral historical description.