L’occasione fa il ladro, a burletta in musica in one act, libretto by Luigi Prividali, was given its first performance at the Teatro San Moisè, Venice, on the 24 November 1812.
The original cast was Gaetano Del Monte (Eusebio), Giacinta Canonici (Berenice), Tommaso Berti (Alberto), Luigi Pacini (Parmenione), Carolina Nagher (Ernestina), Filippo Spada (Martino). The autograph score is in the Paris Conservatoire.
On a stormy night, Don Parmenione and Count Alberto seek refuge in the same country inn. The former is hot on the heels of the sister of a friend of his, who has eloped with a seducer, whilst Count Alberto is on his way to Naples to meet his fiancée for the first time. When Count Alberto leaves the inn to resume his journey, his servant takes Don Parmenione’s bag in mistake for his master’s.
Left alone together, Parmenione and his servant, Martino, realize that this mistake has occurred. Martino, convinced that the circumstances authorize him to take advantage of the misunderstanding, forces open Count Alberto’s bag. Amongst other things it contains Alberto’s passport and the portrait of a young lady, with which Parmenione is enchanted. Deciding that it must be Alberto’s fiancée, Parmenione resolves to impersonate Alberto and marry the girl himself.
At the house of the bride-to-be, the Marchesina Berenice, all is being made ready for the wedding. Berenice, however, is unhappy; her father had promised her in marriage to Alberto before his death, but she does not want to marry him until she is convinced that they really love one another. She therefore decides to change places with her maid and confidante Ernestina.
In this way the Count will be put to a test: with which young lady will he really fall in love? Don Eusebio, Berenice’s uncle and guardian, will help her out in this scheme. Don Parmenione now arrives, dressed as Count Alberto, and meets Ernestina dressed up as the Marchesina. She immediately takes a fancy to the man she supposes to be her mistress’s fiancé, and he seems equally taken with her, even if she looks nothing like the portrait. Meanwhile the real Alberto arrives and meets Berenice dressed as her own maid. This young couple also fall in love at first sight, and whilst she is congratulating herself upon the husband who has been chosen for her, he secretly regrets that he is engaged to be married to someone else, rather than to the pleasing young lady who has aroused such feelings in him on the occasion of their first meeting.
When Don Eusebio and the two couples meet together a scene of great confusion breaks out; it is not at all clear which of the suitors is the authentic Count Alberto, though Parmenione has a distinct advantage in the possession of the Count’s passport.
The plot thickens. Alberto tells his fiancée, Ernestina, that he is prepared to break off their engagement if she does not really love him, and so he demonstrates that he is sincere. Parmenione, meanwhile, makes the mistake of being rude to the supposed maid, who is really Berenice; when she declares that she is the real bride-to-be, he does not know whether to believe her or not, and when she questions him he gets confused when talking about personal matters relating to Alberto. Then Martino, embarrassed by the questions that Don Eusebio and Ernestina fire at him about his master’s true identity, tries to confine his answers to vague generalities.
The two suitors confront one another in Berenice’s presence. The meeting reveals, if not the identities of the men, at least their true feelings: Parmenione has chosen Ernestina, and if Berenice returns Alberto love, he will marry her whether she be a marchesa or not.
Berenice wants to decide her own destiny, wants to know the truth, and is for the moment too angry to care for anything else. In the end it is Parmenione himself who, introducing himself to Don Eusebio and Ernestina, confesses his real name; now it comes out that Ernestina is the very young lady whom Parmenione had set out to find and bring back home. The man she had eloped with abandoned her when unable to prevail upon her virtue. Parmenione offers her his hand, and is accepted. And so everything comes out right; Alverto can marry Berenice and forgive Parmenione. Furthermore it seems that the portrait in the bag was really a picture of Alberto’s sister that he was taking as a present to his future bride, and so Parmenione had embarked on a career as a thief all throught a complete misunderstanding.