Who is believed to be the composer of the 1760 work "The Toy Symphony"?

The Toy Symphony (full title: Cassation in G major for toys, 2 oboes, 2 horns, strings and continuo) is a musical work dating from the 1760s with parts for toy instruments, including toy trumpet, ratchet, bird calls (cuckoo, nightingale and quail), Mark tree, triangle, drum and glockenspiel. It has three movements and typically takes around seven minutes to perform.

It was long reputed to be the work of Joseph Haydn, but later scholarship suggested that it was actually written by Leopold Mozart.

Johann Georg Leopold Mozart (November 14, 1719 – May 28, 1787) was a German composer, violinist, and theorist. He is best known today as the father and teacher of Wolfgang Amadeus Mozart (27 January 1756 – 5 December 1791), and for his 1756 violin textbook "Versuch einer gründlichen Violinschule" (A Treatise on the Fundamental Principles of Violin Playing).

Its authorship is still disputed and other composers have been proposed as the symphony's true author, including Haydn's younger brother Michael Haydn.

Recent research (published in 1996) suggests the Austrian Benedictine monk Edmund Angerer (1740–1794) may be the author, however if his manuscript (from 1765, entitled "Berchtolds-Gaden Musick") is the original, the Toy Symphony was originally written not in G but in C major.

These findings, however, are disputed among scholars. There is reason to believe that the true composer will likely never be known, but it is still widely credited to Leopold.