Vestas Feuer by Pamina and Papageno in "The Magic Flute"), which has the same key and time signature and was the subject of a set of variations for cello and piano by Beethoven (WoO 46), written 1801. Lockwood also discerns a precedent set by Mozart involving formal structure: an "Introduzione"; i.e. Beethoven's scene forms a separable initial section of an opera having some degree of integrity of both plot and harmonic plan; Lockwood calls the "Introduzione" a "miniplay". Three of Mozart's operas begin with such an "Introduzione": "Don Giovanni", "Così fan tutte", and "The Magic Flute". Beethoven's "Introduzione" has a harmonic structure
Mozart and smallpox both children's illness to contend with, the Mozarts spent a total of four months away from Vienna. They eventually returned there and were received in the Imperial court on 19 January, 1768. The Empress, who had by now lost three children to smallpox, conversed with Frau Mozart about the disease. The remainder of the trip was not especially successful. Leopold apparently misinterpreted a chance remark of the Emperor as a firm invitation for Wolfgang to compose an opera; this resulted in Wolfgang writing "La finta semplice". However, the opera went unperformed in Vienna; the singers and musicians did not like