The composer of this opera made so many alterations to the libretto that it was published as by "M.A.", after the original librettist refused to attach his name.  At one point in this opera, the title character sings the aria "Ah, un foco insolito," at the prospect of meeting his friend's sister. Another character who sings "Quel guardo il cavaliere" pretends to have been raised in a convent, and uses the pseudonym "Sofro
The composer of this opera made so many alterations to the libretto that it was published as by "M.A.", after the original librettist refused to attach his name.  At one point in this opera, the title character sings the aria "Ah, un foco insolito," at the prospect of meeting his friend's sister. Another character who sings "Quel guardo il cavaliere" pretends to have been raised in a convent, and uses the pseudonym "Sofronia." Immediately after the marriage contract is signed, that character, Norina, suddenly changes her temper to that of a domineering wife.  The title character joins with Dr. Malatesta in the comic duet "Cheti, cheti immantinente." That title character desires to marry despite his advanced age, but forbids his nephew Ernesto from doing the same. FTP, name this comic opera by Gaetano Donizetti.
The composer of this opera made so many alterations to the libretto that it was published as by "M.A.", after the original librettist refused to attach his name.  
Don Pasquale