Neo-classicism is one of the most important developments in the Twentieth-century music, particularly popular between 1920 to 1950.  Neo-classicism was born at the same time as the general return to rational models in the arts in response to World War I. The years after the war were a time of questioning and re-evaluation in the arts in general.  During this period all the arts were affected by a desire for change, and this was to be found in the paintings of Picasso, the architecture of Corbusier, the writings of James Joyce, and others were influenced by the theory of Darwin.  The musical world too was affected, especially in the breaking-away from traditional major-minor key system or tonality, which has already begun subtly in the end of the nineteenth-century. Major changes include dissonance and key, followed by similar revolutions in rhythm, sound and texture, in order to be ‘set free’ from traditional.  This left many composers feel exhausted and thus prompted them to enter a phase of retrenchment or consolidation of their stylistic advances from the pre-war decade, which emphasizes on musical experimentation to create “modern” music.  Neo-classicism is ‘a style of composing brought by the reintroduction of balanced forms and clearly perceived thematic processes of earlier styles to replace the over-exaggerated gesticulation and absence of form of the late Romanticism’. Despite its widespread consequences for the period 1920-50, ‘neoclassicism is not a concept defined by period, and despite the privileging of certain compositional practices, the concept is neither stylistic nor formal’.

A large number of composers in Europe and the U.S began to draw inspiration from music of the 18th-century, particularly the Baroque and Classical eras.  The musical elements such as tonal centres, clarity of form, and melodic shape were borrowed by the neo-classical composers and to these elements, the composer added modern flavourings such as ‘quirky rhythms, spiky dissonances and large amount of chromaticism’. Traditional instrumental and vocal types were emphasized, and ‘compositional techniques of earlier times were revived in a modern guise’. The motivation for the neo-classicism was to simply acknowledge tradition.  Its aim was not to revive old musical idioms.  Stravinsky, perhaps the most important neo-classical composer, spoke emphatically of the necessity of tradition in music:

“…Whereas tradition results from a conscious and deliberate acceptance.  A real tradition is not the relic of a past irretrievably gone; it is a living force that animates and informs the present.”

Neo-classicism most obvious traits are melodies, which use ‘the tritone as a stable interval, and the composers coloristically add dissonant notes to ostinati and block harmonies, along with the free mixture of polyrhythm’. Triads and diatonic collections of pitches are preferred, and straightforward melody and homophonic textures were reasserted.  The neo-classical movement was quite widespread in Europe and the U.S. and won greater audience acceptance more quickly.  Some of the more recognized neo-classical composers and their major works are: Stravinsky’s Pulcinella, Symphony in C, Symphony in three movements, Dumbarton Oaks Concerto, Symphony of Psalm, Concerto in E flat for chamber orchestra; Hindemith’s Kammermusik, Das Marienleben, Mathis der Maler; Britten’s Billy Budd, String Quartet no.3, Peter Grimes, War Requiem; Prokofiev’s Classical Symphony; Honegger’s Pacific 231; Tippet’s Concerto for Double String Orchestra and Vaughan William’s Violin Concerto.

Stravinsky announced his new style in 1923 with the stripped-down and delicately scored ‘Octet’ for wind instruments.  Its clear harmonies looked back to the Classical music era of Mozart with its simpler combinations of rhythm and melody.  This piece was a direct response to the complexities of the musical style of the Second Viennese School, which was led by Schoenberg and his two pupils, Webern and Berg.  Concertino style is another important characteristic applied by Stravinsky in his Symphonies for Wind Instruments in 1920 and Dumbarton Oaks Concerto in 1938. The Dumbarton Oaks Concerto was composed in the vein of the Bach Brandenburg Concertos. Another example was his Symphony in C, which he employs a small orchestra and fragments the orchestra into instrumental groups, contrasted one against the other. Again in the symphony in three movements, which employs a slightly larger orchestra, Stravinsky divided the strings into concertino and ripieno sections, as was also the case in Pulcinella. With the symphony in three movements he introduced a chamber-music flavour into the symphony. In 1927, Stravinsky composed ballet Apollon musagete, scored for strings.  This ballet score was probably his first in classical style, which is conceived in the style first revealed by the ‘Octet’ for winds.

In Germany, Hindemith composed his first important work in neo-classical style, song cycle Das Marienleben (The Life of Mary) in 1923.  The musical form is that of the Baroque passacaglia with a continuous variations upon a five-bar ground bass.  Other neo-classical elements of the setting reside in its ‘rigidly contrapuntal texture, triadic points of arrival and departure, and regularity of rhythm and phrasing’. The influence of Bach is recognizable in Hindemith’s music, for example in his Ludus Tonalis, which has a strong similarity in purpose and method to the Well-tempered Clavier. Hindemith’s neo-classicism is very different to the works by Stravinsky.  His music owes more to Bach than Mozart. Hindemith most popular work, Symphonic Metamorphoses of Themes by Carl Maria von Weber, written in 1943, takes melodies from various works by Weber, mainly his piano duet.

Prokofiev's music often gives the impression of music from the Classical Period.  His Classical Symphony (officially his Symphony No.1 in D) is very similar in form and style to symphonies by composers such as Haydn, but has some more modern features very characteristic of Prokofiev.

In the exact sense of the Russian formalists, the impact of neoclassicism was not widespread; it remained essentially centred on Stravinsky, particularly on his works up until the mid 1930s.  This was especially true when Stravinsky himself turned to Serialism in his Canticum Sacrum.  Thus, it marked an end to neo-classicism in his own work if not for the musical world