In the spring of 1913, Beatrice von Dovsky presented the libretto to the composer, who prepared a piano sketch during the following summer. He completed the opera during his eight-month military duty as a medical soldier in France and Belgium. The subject was very topical at the time, because the painting by Leonardo da Vinci had been stolen from the Louvre in 1911, and rediscovered in Florence in 1913.
A couple is visiting a palace in Florence. A lay brother tells them the history of the house and its occupants, among them Fiordalisa Gherardini, Francesco Giocondo's wife painted by Leonardo da Vinci.
Act 1
Together with his guests, Francesco is celebrating the last night of the Carnival, while his wife, the beautiful Mona Lisa, has gone out for confession. A procession led by the courtesan Ginevra passes, but the preacher Savonarola together with a chorus of monks interrupts the Carnival activities with a call to do penance. Ginevra is invited into the house, and explains to Lisa, just returning from confession, that sin is the salt of all delight. Francesco explains to Pietro why he is consumed with jealousy. On the painting made by Leonardo, his wife smiles in a way that she has never smiled at him. She has always been reserved and serious towards him, and Francesco wants to solve the enigma of her smile. Giovanni has come on behalf of the Pope to purchase a pearl form Francesco's famous collection, which is kept in a shrine specifically designed in a way that no one can breathe in it for longer than an hour. In order to preserve the pearls' brightness Lisa has to wear them every night. Lisa and Giovanni know each other, they have been in love before she was unhappily married to Francesco. Giovanni persuades her to flee with him the next morning, when he will come back to collect the pearl. When Francesco returns, he sees the mysterious smile on his wife's face and suspects he has a rival. He systematically locks all exits, so Giovanni has no other choice than to hide himself in the pearls' shrine. Francesco plays a diabolical game with Lisa, pretending not to have noticed anything, intentionally misinterpreting her unrest and fear for Giovanni's life as love and desire. Lisa goes along with this after Francesco promises her to fulfill a wish. She succumbs to his desire, and then asks for the key to the shrine. Again, Francesco intentionally misinterprets this as her being jealous of the pearls, and to prove his "love" he throws the only key into the river.
Act 2
The next morning, Lisa can hardly remember what happened the night before. She blames herself for having done nothing to save Giovanni, hopes for a sign of life from the shrine, but in vain: Giovanni has suffocated. Lisa's stepdaughter Dianora enters, and gives her the key to the shrine she had found in her boat the night before. Francesco appears, irritated by his wife's self-control. When she presents him with the key, he assumes Giovanni has escaped. Lisa now insists on wearing the pearls, and with a smile she waits for the moment Francesco enters the shrine. She then locks the door behind him.
Epilogue
The lay brother's story comes to an end. The couple leave and the lay brother thinks he recognises Mona Lisa in the woman.
Recordings
In 1995 CPO released a 1994 recording, with Klauspeter Seibel conducting the Kiel Philharmonic Orchestra.
