The Symphony No. 43 in E-flat major, Hoboken I/43, is a symphony

Symphony

A symphony is an extended musical composition in Western classical music, scored almost always for orchestra. A symphony usually contains at least one movement or episode composed according to the sonata principle...

 by Joseph Haydn

Joseph Haydn

Franz Joseph Haydn , known as Joseph Haydn , was an Austrian composer, one of the most prolific and prominent composers of the Classical period. He is often called the "Father of the Symphony" and "Father of the String Quartet" because of his important contributions to these forms...

. Since the nineteenth century it has been referred to by the subtitle "Mercury

Mercury (mythology)

Mercury was a messenger who wore winged sandals, and a god of trade, the son of Maia Maiestas and Jupiter in Roman mythology. His name is related to the Latin word merx , mercari , and merces...

". The symphony was composed by 1771

1771 in music

- Events :*Foundation of the Royal Theatre Ballet School in Copenhagen, Denmark.*The Chevalier de Saint-Georges is appointed maestro of the Concert des Amateurs in Paris....

. It is scored for two oboe

Oboe

The oboe is a double reed musical instrument of the woodwind family. In English, prior to 1770, the instrument was called "hautbois" , "hoboy", or "French hoboy". The spelling "oboe" was adopted into English ca...

s, bassoon

Bassoon

The bassoon is a woodwind instrument in the double reed family that typically plays music written in the bass and tenor registers, and occasionally higher. Appearing in its modern form in the 19th century, the bassoon figures prominently in orchestral, concert band and chamber music literature...

, two horn

Horn (instrument)

The horn is a brass instrument consisting of about of tubing wrapped into a coil with a flared bell. A musician who plays the horn is called a horn player ....

s and strings

String instrument

A string instrument is a musical instrument that produces sound by means of vibrating strings. In the Hornbostel-Sachs scheme of musical instrument classification, used in organology, they are called chordophones...

.

The work is in four movements:

1. Allegro, 3/4
2. Adagio, 2/4
3. Menuet
   Minuet
   A minuet, also spelled menuet, is a social dance of French origin for two people, usually in 3/4 time. The word was adapted from Italian minuetto and French menuet, and may have been from French menu meaning slender, small, referring to the very small steps, or from the early 17th-century popular...
   
    & Trio, 3/4
4. Allegro, 2/2

H. C. Robbins Landon

H. C. Robbins Landon

Howard Chandler Robbins Landon was an American musicologist.He was born in Boston, Massachusetts and studied music at Swarthmore College and Boston University. He subsequently moved to Europe where he worked as a music critic. From 1947 he undertook research in Vienna on Joseph Haydn, a composer...

 describes the slow movement "as a chamber symphony opens with muted strings". It is the only movement of any of Haydn's symphonies to be in the key of A flat major.