The indication "K." or "KV" refers to Köchel Verzeichnis (Köchel catalogue), i.e. the (more or less) chronological (i.e. by composition date) catalogue of Mozart's works by Ludwig von Köchel. This catalog has been amended several times, leading to ambiguity over some KV numbers (see e.g. Symphony No. 25).
The compositions of Mozart listed below are grouped thematically, i.e. by type of composition. Not all thematic groups of Mozart's works have a separate numbering that is generally accepted: Köchel only numbers symphonies (1 to 41), piano concertos (1 to 27, leaving out some early transcriptions by Mozart) and a few other groups. On the other hand, for most chamber music and vocal music there is no such numbering (or at least no generally accepted one).
Only relatively few of Mozart's compositions have opus numbers, as not so many of his compositions were published during his lifetime, so numbering by opus number proves quite impractical for Mozart compositions.
Mozart's symphonic production covers a 24-year interval, from 1764 to 1788. According to most recent investigations, Mozart wrote not just the 41 symphonies reported in traditional editions, but up to 68 complete works of this type. However, by convention, the original numbering has been retained, and so his last symphony is still known as "No. 41". Some of the symphonies (K. 297, 385, 550) were revised by the author after their first versions.
Childhood symphonies (1764–1771)
These are the numbered symphonies from Mozart's early childhood.
There are also several "unnumbered" symphonies from this time period. Many of them were given numbers past 41 (but not in chronological order) in an older collection of Mozart's works (Mozart-Werke, 1877–1910, referred to as "GA"), but newer collections refer to them only by their entries in the Köchel catalogue. Many of these cannot be definitively established as having been written by Mozart (see here).
These symphonies are sometimes subcategorized as "Early" (1771–1773) and "Late" (1773–1777), and sometimes subcategorized as "Germanic" (with minuet) or "Italian" (without minuet). None of these were printed during Mozart's lifetime.
Although not counted as "symphonies" the three Divertimenti K. 136–138, in 3-movement Italian overture style, are sometimes indicated as "Salzburg Symphonies" too.
There are also several "unnumbered" symphonies from this time period that make use of music from Mozart's operas from the same time period. They are also given numbers past 41.
For years this was categorized as a Mozart symphony, but later scholarship determined that it was actually composed by Michael Haydn (Symphony No. 25), and Mozart wrote only the slow introduction for it.
The three final symphonies (Nos. 39–41) were completed in about three months in 1788. It is likely that Mozart hoped to publish these three works together as a single opus, but they remained unpublished until after his death. One or two of them might have been played in public in Leipzig in 1789.
Mozart's concertos for piano and orchestra are numbered from 1 to 27. The first four numbered concertos are early works. The movements of these concertos are arrangements of keyboard sonatas by various contemporary composers (Raupach, Honauer, Schobert, Eckart, C. P. E. Bach). There are also three unnumbered concertos, K. 107, which are adapted from piano sonatas by J. C. Bach. Concertos 7 and 10 are compositions for three and two pianos respectively. The remaining twenty-one, listed below, are original compositions for solo piano and orchestra. Among them, fifteen were written in the years from 1782 to 1786, while in the last five years Mozart wrote just two more piano concertos.
36 Cadenzas, K. 624/626a (1768-91; the list of all the cadenzas that Mozart wrote for his own piano concertos and piano concertos of contemporaries)
Violin concertos
Mozart's five violin concertos were written in Salzburg around 1775, except the first around 1773. They are notable for the beauty of their melodies and the skillful use of the expressive and technical characteristics of the instrument, though Mozart likely never went through all the violin possibilities that others (e.g. Beethoven and Brahms) did after him. (Alfred Einstein notes that the violin concerto-like sections in the serenades are more virtuosic than in the works titled Violin Concertos.)
Arguably the most widely played concertos for horn, the four Horn Concertos are a major part of most professional horn players' repertoire. They were written for Mozart's lifelong friend Joseph Leutgeb. The concertos (especially the fourth) were written as virtuoso vehicles that allow the soloist to show a variety of abilities on the valveless horns of Mozart's day.
The Horn Concertos are characterized by an elegant and humorous dialogue between the soloist and the orchestra. Many of the autographs contain jokes aimed at the dedicatee.
Clarinet Concerto in A major, K. 622 (1791; originally was for basset horn and was in the key of G major)
Bassoon Concerto in B♭ major, K. 230a/Anh. C 14.03 (Discovered in set of parts in The Hague attributed to Mozart; authenticity widely doubted from start. Most likely composed by François Devienne)
Oboe Concerto in E♭ major, K.Anh.C 14.06 (Doubtful authenticity)
Others
Basset Horn Concerto in G major, K. 584b (fragment; transcribed and finished to the well-known clarinet concerto)
Mozart's earliest composition attempts begin with piano sonatas and other piano pieces, as this is the instrument on which his musical education took place. Almost everything that he wrote for piano was intended to be played by himself (or by his sister, also a proficient piano player). Examples of his earliest works are those found in Nannerl's Music Book. Between 1782 and 1786, Mozart wrote 20 works for piano solo (including sonatas, variations, fantasias, suites, fugues, rondo) and works for piano four hands and two pianos.
Fugue in C minor for Two Keyboards, K. 426 (1783) (transcribed in 1788 for string quartet as K. 546)
Larghetto and Allegretto for Two Pianos in E♭ major, K. deest (completed by Maximilian Stadler)
Others
Allegro in C minor for Two Pianos, K.Anh. 44/426a (1783-86; fragment)
Chamber music
Chamber music with piano
Violin music
Mozart also wrote sonatas for keyboard and violin. For the most part, these are keyboard-centric sonatas where the violin plays a more accompanying role. In later years, the role of the violin grew to not just a support to the other solo instrument, but to build a dialogue with it.
The 'Violin Sonatas', KV 10–15, are unique in that they include an ad lib. cello part along with the score for violin and keyboard. The Neue Mozart-Ausgabe (1966) therefore includes them along with the other keyboard trios, although the Köchel catalogue (K6, 1964) lists them as normal violin sonatas.
Much more stylistically developed. In Vienna Mozart is believed to have heard the op. 17 and op. 20 quartets of Joseph Haydn, and had received from them a deep impression.
Mozart returned to the quartet in the early 1780s after he had moved to Vienna, met Haydn in person, and developed a friendship with the older composer. Haydn had just published his set of six quartets, Op. 33, which are thought to have been a stimulus to Mozart in returning to the genre. These quartets are often regarded as among the pinnacles of the genre.
Mozart's last three quartets, dedicated to the King of Prussia, Friedrich Wilhelm II, are noted for the cantabile character of the parts for cello (the instrument played by the king himself), the sweetness of sounds and the equilibrium among the different instruments.
Fugues for 2 Violins, Viola and Cello, K. 405 (1782)
Adagio and Fugue in C minor for 2 Violins, Viola and Cello, K. 546 (1788) (a transcription from Fugue in C minor for Two Keyboards, K. 426)
Canon in C major for 2 Violins, Viola and Cello, K. Anh. 191/562c (1788, attribution uncertain)
String Quartet in E minor, K. 417d (1789; fragment)
String Quartet in G minor, K. 587a (1789; fragment)
String quintets
The string quintets (K. 174, 406, 515, 516, 593, 614), for two violins, two violas and cello. Charles Rosen wrote that "by general consent, Mozart's greatest achievement in chamber music is the group of string quintets with two violas."[2]
The production for instrumental ensembles includes several divertimenti, cassations, notturni, serenades, marches, dances, and a quodlibet, besides, of course, his symphonies. Mozart's production for orchestra is written for string ensembles (like the early Divertimenti K. 136–138), as well as for wind ensembles and the varied combinations of strings and winds.
Serenades
Cassation in D major (Serenade No. 1), K. 100/62a (1769)
4 Contredanses in F major (Serenade No. 2), K. 101/250a (1776)
Serenade No. 3 in D major, "Antretter", K. 185/167a (1773)
Serenade No. 4 in D major, "Colloredo", K. 203/189b (1774)
Serenade No. 6 in D major, "Serenata Notturna", K. 239 (1776)
Serenade No. 7 in D major, "Haffner", K. 250/248b (1776)
Notturno in D for Four Orchestras (Serenade No. 8), K. 286 (1776–77) (each of the four "orchestras" composed of 2 French horns in D, 2 violins, viola and cello)
March and Divertimento in C major; the music title when the two marches of K. 214 are played before and after the three movements of Symphony in C major, K. 208+(102/213c) (Il re pastore) (1772, 1775)
String Quartet No. 2 in D major, K. 155/134a ("Divertimento") (1772)
String Quartet No. 5 in F major, K. 158 ("Divertimento") (1772–73)
String Quartet No. 6 in B♭ major, K. 159 ("Divertimento") (1773)
Incomplete
Divertimento in F major, K. 288/246c (1777) (incomplete)
Divertimento in D major, K. 320B (1772–73) (incomplete)
Marches
March in D major, K. 62 (Introduction to K. 100 Serenade, also used in Mitridate, re di Ponto) (1769)
March in D major, K. 189/167b (probably to open/close K. 185 Serenade) (1773)
March in C major, K. 214 (two marches opening and closing the divertimento—three movements of Symphony in C major, K. 208+(102/213c)—Il re pastore) (1775)
March in D major, K. 215/213b (to open and/or close Serenade, K. 204) (1775)
March in D major, K. 237/189c (to open and/or close Serenade, K. 203) (1774)
March in F major, K. 248 (for use with Divertimento No. 10, K. 247) (1776)
March in D major, K. 249 (to open and/or close Serenade, "Haffner", K. 250) (1776)
March in D major, K. 290 (for use with Divertimento No. 7, K. 205/167A) (1772)
March in D major, K. 335/320a, No. 1 (probably to open Serenade, "Posthorn", K. 320) (1779)
March in D major, K. 335/320a, No. 2 (probably to close Serenade, "Posthorn", K. 320) (1779)
March in C major, K. 408/383e, No. 1 (1782)
March in D major, K. 408/385a, No. 2 (1782)
March in C major, K. 408/383F, No. 3 (1782)
March in D major, K. 445/320c (for use with Divertimento No. 17, K. 334) (1780)
Others
Cassation in G major, K. 63, first movement march (1769)
Divertimento No. 11 in D major, K. 251, sixth movement (1776)
March in D major, K. 544 (1788; lost)
Incomplete
March in B♭ major, K. 384b (1782?) (incomplete)
Dances
Autograph manuscript of the Minuet K.164, number 5
In his production of minuets, Mozart generally followed Haydn's example, preferring the slow character of the dance. Allemandes written between 1787 and 1791 were mainly for public balls in Vienna. In the Contredanse production, also written mainly in Vienna, some examples of program music are found, like Il Temporale, K. 534, La Bataille, K. 535, Canary, K. 600/5, etc.
Musik zu einer Pantomime: Pantalon und Colombine (Music to a Pantomime) in D major, K. 446/416d (1783, fragment)
Sacred music
Mozart's sacred music is mainly vocal, though also instrumental examples exist, like the seventeen Sonate da chiesa, composed between 1772 and 1780. His sacred music presents a rich stylistic mosaic: Gregorian choral elements meet rigorous counterpoint, and even operatic elements can sometimes emerge. Stylistic unity and consistency is present over all his sacred music work.
The following are compositions written for the Masonic Lodge:
Song, "Lobegesang auf die feierliche Johannisloge" ("O heiliges Band der Freundschaft treuer Brüder") [O sacred bond of friendship between true brothers], K. 148/125h, (1772)
Cantata Dir, Seele des Weltalls, K. 429/468a (fragment, completed by Maximilian Stadler) (1783)
Song, "Lied zur Gesellenreise: Die ihr einem neuen Grad", K. 468, "for use at installation of new journeymen" (1785)
Cantata for tenor, male chorus, and orchestra Die Maurerfreude (The Freemason's Joy) K. 471 (1785)
Two songs for tenor and organ used for the opening and closing ceremonies of the lodge in Austria "Zur Neugekrönten Hoffnung":
"Zerfließet Heut, Geliebter Brüder", K. 483 (1786)
"Ihr Unsre Neuen Leiter", K. 484 (1786)
The Little German Cantata (Kleine Deutsche Kantate) ("Die ihr die unermeßlichen Weltalls Schöpfer ehrt"), for tenor and piano, for use at meetings of the Colony of the Friends of Nature, K. 619 (1791)
The Little Masonic Cantata (Kleine Freimaurer-Kantate [es]) "Laut verkünde unsre Freude", for soloists, male chorus, and orchestra, K. 623 (1791)
Song, "Laßt uns mit geschlungen Händen", K. 623a, ("for the close of the lodge" and intended final chorus to K. 623) (1791; attribution uncertain)