"La donna è mobile" [la ˈdɔnna ɛ ˈmmɔːbile] (The woman is fickle) is the Duke of Mantua's canzone from the beginning of act 3 of Giuseppe Verdi's operaRigoletto (1851). The inherent irony is that the Duke, a callous playboy, is the one who is mobile ("inconstant"). Its reprise towards the end of the opera is chilling, as Rigoletto realizes from the sound of the Duke's lively voice coming from within the tavern (offstage), that the body in the sack over which he has grimly triumphed is not that of the Duke after all: Rigoletto had paid Sparafucile, an assassin, to kill the Duke but Sparafucile deceived him by killing Gilda, Rigoletto's beloved daughter, instead.
The canzone is famous as a showcase for tenors. Raffaele Mirate's performance of the bravuraaria at the opera's 1851 premiere was hailed as the highlight of the evening. Before its first public performance (in Venice), it was rehearsed under tight secrecy: a necessary precaution, because it proved to be catchy and soon after its first public performance every gondolier in Venice was singing it.
The almost comical-sounding theme of "La donna è mobile" is introduced immediately, and runs as illustrated (transposed from the original key of B major). The theme is repeated several times in the approximately two to three minutes it takes to perform the aria, but with the important—and obvious—omission of the last bar. This has the effect of driving the music forward as it creates the impression of being incomplete and unresolved, which it is, ending not on the tonic or dominant but on the submediant. Once the Duke has finished singing, however, the theme is once again repeated; but this time it includes the last, and conclusive, bar and finally resolving to the tonic. The song is strophic in form with an orchestral ritornello.