Symphony No. 37 (Michael Haydn)

Symphony No. 37 in B-flat major, Perger 29, MH 476, is a symphony composed by Michael Haydn. It is often confused with Wolfgang Amadeus Mozart's Symphony No. 37 in G major, K. 444/425a, because Mozart only composed the slow introduction (the first 26 measures) to Haydn's work. The rest of the symphony is entirely Michael Haydn's composition.

Haydn composed the symphony in Salzburg in 1784. Mozart, who was residing in Salzburg at the time, apparently lacked a symphony to be performed for a concert and borrowed Haydn's score. Rather than simply performing it as is, Mozart composed a new, slower introduction to replace the existing one.

The symphony itself is in four movements:

1. Andante sostenuto (Mozart's introduction, in G major)
2. Allegro con spirito (Haydn's movement, in B-flat major)
3. Andante un poco sostenuto (Haydn's movement, in E-flat major)
4. Presto ma non troppo (Haydn's movement, in B-flat major)

While Mozart's contribution is significant due to his fame and the inherent quality of his writing, it's crucial to acknowledge Michael Haydn as the primary composer of the symphony. Performances and recordings sometimes clarify the authorship, distinguishing between the Mozart introduction and the Haydn symphony. The confusion surrounding the symphony's authorship has led to some works cataloging it solely under Mozart's name, though scholarship increasingly recognizes Haydn's substantial contribution.