The Serenade for strings in G major, K 525, also known as Eine kleine Nachtmusik ("A little night music" or less literally, "A little serenade"), is one of the most popular compositions by Wolfgang Amadeus Mozart. Mozart wrote it in 1787 in Vienna while working on Don Giovanni. It is not known why or for whom he wrote this piece.
The work was written for a chamber ensemble of two violins, viola, and cello with optional double bass. It is often performed today with more than one person to a part.

Allegro
The second movement is a "Romanza", in Andante and contrasting and slower than the first movement. It is in a "section rondo form" and is similar to the sonata rondo form (ABACA). The first theme (A) is graceful and lyrical. It is followed by a more rhythmical second theme (B). The first theme returns (A) and is followed by the third theme (C), which is darker than the first two and includes a touch of C minor. The first theme (A) returns to finish the movement. The key is in C major, which is the sub-dominant of G major

Romanze
The third movement is a minuet and trio (ABA). The movement is in the tonic key, which is in G major and is fairly quick with a tempo of Allegretto. It contains two themes, a minuet and a trio. The movement begins with the minuet (A), then the trio theme enters (B), and it ends with the minuet (A). It ends in the tonic key, which is in G major.

Rondo
Mozart listed this work as having five movements in his own catalogue of his works. ("Allegro - Minuet and Trio. - Romance, Minuet and Trio and Finale.")