The famous finale to Mozart’s comic opera begins when the door to the closet in a room Count Almaviva’s estate is opened. Both the Count and Countess think Cherubino, the Count’s page, is in the closet. The Count is about to break down the door and then decides to use his sword on the page – he’s jealous. To both their astonishment Susanna emerges from the closet. She’d taken Cherubino’s place; he jumped out of a window.
The Count demands an explanation; the Countess tells him it is a practical joke, to test his trust in her. Shamed by his jealousy, the Count begs for forgiveness. When the Count presses about the anonymous letter, Susanna and the Countess reveal that the letter was written by Figaro, and then delivered by Basilio. Figaro then arrives and tries to start the wedding festivities, but the Count berates him with questions about the anonymous note. Just as the Count is starting to run out of questions, Antonio the gardener arrives, complaining that a man has jumped out of the window and damaged his carnations while running away. Antonio adds that he tentatively identified the running man as Cherubino, but Figaro claims it was he himself who jumped out of the window, and pretends to have injured his foot while landing. Figaro, Susanna, and the Countess attempt to discredit Antonio as a chronic drunkard whose constant inebriation makes him unreliable and prone to fantasy, but Antonio brings forward a paper which, he says, was dropped by the escaping man. The Count orders Figaro to prove he was the jumper by identifying the paper (which is, in fact, Cherubino’s appointment to the army). Figaro is at a loss, but Susanna and the Countess manage to signal the correct answers, and Figaro triumphantly identifies the document. His victory is, however, short-lived: Marcellina, Bartolo, and Basilio enter, bringing charges against Figaro and demanding that he honor his contract to marry Marcellina, since he cannot repay her loan. The Count happily postpones the wedding in order to investigate the charge. (From Wikipedia synopsis).
The finale is through written and is different from anything that had been previously composed. The music through the following keys: E-flat Major (“Esci omai, garzon malnato”); B-flat Major (“Susanna! Susanna!”; G Major (“Signore, di fuori son già i suonatori”); C Major (“Conoscete, signor Figaro, questo foglio chi vergò?”); F Major (“Ah, signor, signor!”); B-flat Major (“Vostre dunque saran queste carte”); E-flat Major (“Voi signor, che giusto siete”). See Timothy Judd’s analysis of this finale. It ends with all seven principals singing together.
This is the apogee of 18th century comic opera. It remained the standard of excellence until Gioacchino Rossini emerged in the second decade of the 19th century with a different, but equally brilliant musical language. A language which all the Italian composers who followed him learned to speak.
The video linked below is from a student performance in Vienna in 2014. These trainees are obviously ready for prime time. If the YouTube video goes dark, a link below it will provide an alternate site where it can be viewed.