Così fan tutte

Two young officers bet their cynical friend Don Alfonso that their fiancées are faithful. Alfonso is certain they are not, and proposes a test: the men will pretend to leave for war, return in disguise, and attempt to seduce each other's lovers. The women resist, then don't. Both of them succeed. Mozart and his librettist Lorenzo da Ponte set this up as a comedy, which it is — the disguises are absurd, the complications multiply with the precision of a farce. But Così fan tutte is also Mozart's most uncomfortable opera, because by the final act it is not clear whether the test revealed something true about these four people or created it. Soave sia il vento — the trio sung as the soldiers pretend to leave — is among the most beautiful things Mozart ever wrote, and it serves a story in which no one comes out clean.