This Mozart's opera from 1790 tries to discover whether female fidelity is truly like the bird phoenix – it is spoken of, but no-one has ever encountered it. Perhaps the answer lies in the title itself. Così fan tutte is the last opera Mozart created with librettist Lorenzo da Ponte. It is believed that the emperor Joseph II himself proposed to Mozart to compose an opera using this theme of female fidelity. Mozart and Da Ponte based the work on texts on espousal substitution from the 13th century and some variations on this topic can also be found in Boccacio's stories The Decameron and in some Shakespeare's works, etc. The plot begins in a tavern where two officers publicly declare how their fiancées will be faithful. Don Alfonso is sceptical and proposes a wager that will prove them wrong. The officers pretend to go to war, disguise themselves and thus initiate a series of intrigues that reveal various aspects of love, seducing, flirting, deception, and funny situations which show how much strength every human being possesses to fight off deceit. Although this opera in the past had not been placed among Mozart's best works, in the 20th century it became a must-have on the repertoire of all large world opera houses. The Opera of the Croatian National Theatre in Zagreb will premiere this Mozart's opera of great music beauty with Valentin Egel as conductor and Alessio Pizzech as stage director.