The six string quartets, K. 155-160, were composed by Wolfgang Amadeus Mozart

Wolfgang Amadeus Mozart

Wolfgang Amadeus Mozart , baptismal name Johannes Chrysostomus Wolfgangus Theophilus Mozart , was a prolific and influential composer of the Classical era. He composed over 600 works, many acknowledged as pinnacles of symphonic, concertante, chamber, piano, operatic, and choral music...

 in late 1772 and early 1773. Because they were composed in Milan

Milan

Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...

 while he was working on his opera Lucio Silla

Lucio Silla

Lucio Silla, K. 135, is an Italian opera in three acts composed by Wolfgang Amadeus Mozart. The libretto was written by Giovanni de Gamerra.It was first performed on 26 December 1772 at the Regio Ducal Teatro in Milan....

, they are popularly known as the Milanese Quartets. Before this set was composed, Mozart had written one earlier string quartet

String quartet

A string quartet is a musical ensemble of four string players – usually two violin players, a violist and a cellist – or a piece written to be performed by such a group...

 (K. 80 in 1770), so these six quartets are ordinally numbered from No. 2 to No. 7. The quartets are written in a plan of keys of D-G-C-F-B-E following the circle of fifths

Circle of fifths

In music theory, the circle of fifths shows the relationships among the 12 tones of the chromatic scale, their corresponding key signatures, and the associated major and minor keys...

.

All six quartets have only three movements. Four of the quartets (K. 156-159) have slow movements in the minor mode. The finales are generally lightweight, usually minuet

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...

s or rondo

Rondo

Rondo, and its French equivalent rondeau, is a word that has been used in music in a number of ways, most often in reference to a musical form, but also to a character-type that is distinct from the form...

s.

Quartet No. 2 in D major, K. 155

Written in the fall of 1772 in Bolzano.

1. Allegro
2. Andante
3. Molto allegretto

Quartet No. 3 in G major, K. 156

Written at the end of 1772 in Milan.

1. Presto
2. Adagio
3. Tempo di minuetto

Quartet No. 4 in C major, K. 157

Written at the end of 1772 in Milan and premiered in early 1773.

1. Allegro
2. Andante
3. Presto

Quartet No. 5 in F major, K. 158

Written and premiered in early 1773 in Milan.

1. Allegro
2. Andante un poco allegretto
3. Tempo di minuetto

Quartet No. 6 in B flat major, K. 159

Written and premiered in early 1773 in Milan.

1. Andante
2. Allegro
3. Rondo

Quartet No. 7 in E flat major, K. 160

Written and premiered in early 1773 in Milan. The second movement is remarkable for its non-tonic opening http://www.musictheoryresources.com/members/MTA_2_1b.htm.

1. Allegro
2. Un poco adagio
3. Presto