oca del Cairo, L’, K422 (The Goose of Cairo) (1783–4). Early in 1783, Mozart was on the lookout for a new opera libretto; Joseph II had just established an opera buffa troupe in Vienna and Mozart was eager to show himself equal to the challenge of Italian comic opera after the success of Die Entführung aus dem Serail (1782). Searching for a suitable subject, he worked his way through more than a hundred texts sent to him from Italy. Finding nothing that inspired him, however, Mozart eventually resolved to request a brand-new libretto from Giovanni Varesco, the chaplain to the Archbishop of Salzburg; the result was the ill-fated project L'oca del Cairo, an unfinished opera buffa that survives only as a fragmentary first act.

Varesco had collaborated with Mozart before, on the opera seria Idomeneo, commissioned in 1780 by the Munich court. That Varesco had been resident in Salzburg had given Mozart ample opportunity to intervene in the design of the libretto during the early stages of its composition; with the constant help and mediation of his father, Mozart likewise became closely involved in the creation of the text of L'oca del Cairo. Indeed, Mozart's constant tinkering with the libretto for Idomeneo had caused considerable friction between the composer and the poet, and one can surmise that the composer's rather demanding attitude, coupled with Varesco's own shortcomings and relative inexperience as a librettist, were contributing factors in the premature demise of L'oca del Cairo.