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
Piano concertos by Wolfgang Amadeus Mozart it was probably J.C. Bach, whom Mozart admired, who introduced the structural innovation of allowing the keyboard to introduce new thematic material in its first entry. Concertos Nos 1–4 (K. 37, 39, 40 and 41) are orchestral and keyboard arrangements of sonata movements by other composers. The next three concertos (K. 107/1, 2 and 3), which are not numbered, are arrangements of piano sonatas by J.C. Bach (Op 5. Nos. 2, 3, and 4, all composed by 1766). Based on handwriting analysis of the autographs they are believed to date from 1771–72. Concerto No. 5, K. 175 from 1773 was