The title, Così fan tutte, literally means "So do they all", using the feminine plural (tutte) to indicate women. It is usually translated into English as "Women are like that".
In a cafe, two officers express certainty that their fiancées will be eternally faithful. Don Alfonso expresses skepticism and claims that there is no such thing as a faithful woman. He lays a wager with the two, claiming he can prove in a day's time that theirs, like all women, are fickle. The wager is accepted: the two officers will pretend to have been called off to war; soon thereafter they will return in disguise and each attempt to seduce the other's lover.
Mozart disliked Adriana Ferrarese del Bene, da Ponte's arrogant mistress for whom the role of Fiordiligi had been created. Knowing her idiosyncratic tendency to drop her chin on low notes and throw back her head on high ones, Mozart filled her showpiece "Come scoglio" with constant leaps from low to high and high to low in order to make her head "bob like a chicken" onstage.
