Franz Peter Schubert was an Austrian composer. Schubert already died before his 32nd birthday, but was extremely prolific during his lifetime. His output consists of over six hundred secular vocal works (mainly Lieder), seven complete symphonies, sacred music, operas, incidental music and a large body of chamber and piano music. Appreciation of his music while he was alive was limited to a relatively small circle of admirers in Vienna, but interest in his work increased significantly in the decades following his death. Felix Mendelssohn, Robert Schumann, Franz Liszt, Johannes Brahms and other 19th-century composers discovered and championed his works. Today, Schubert is ranked among the greatest composers of the late Classical and early Romantic eras and is one of the most frequently performed composers of the early nineteenth century.
It was in the genre of the Lied that Schubert made his most indelible mark. Prior to Schubert's influence, Lieder tended toward a strophic, syllabic treatment of text, evoking the folksong qualities engendered by the stirrings of Romantic nationalism. Schubert expanded the potentialities of the genre like no other composer before.

Claude Debussy was a French composer. He and Maurice Ravel were the most prominent figures associated with impressionist music, though Debussy disliked the term when applied to his compositions. He was made Chevalier of the Legion of Honour in 1903. He was among the most influential composers of the late 19th and early 20th centuries, and his use of non-traditional scales and chromaticism influenced many composers who followed.
Debussy's music is noted for its sensory content and frequent usage of non-traditional tonalities. The prominent French literary style of his period was known as Symbolism, and this movement directly inspired Debussy both as a composer and as an active cultural participant Among his most famous works are his Clair de Lune, his Three Nocturnes and his orchestral piece La Mer.

Joseph Maurice Ravel was a French composer who is often associated with impressionism along with his elder contemporary Claude Debussy, although both composers rejected the term. In the 1920s and 1930s Ravel was internationally regarded as France's greatest living composer.
Born to a music-loving family, Ravel attended France's premier music college, the Paris Conservatoire; he was not well regarded by its conservative establishment, whose biased treatment of him caused a scandal. After leaving the Conservatoire Ravel found his own way as a composer, developing a style of great clarity, incorporating elements of baroque, neoclassicism and, in his later works, jazz. He liked to experiment with musical form, as in his best-known work, Boléro (1928), in which repetition takes the place of development. He made some orchestral arrangements of other composers' music, of which his 1922 version of Mussorgsky's Pictures at an Exhibition is the best known.
As a slow and painstaking worker, Ravel composed fewer pieces than many of his contemporaries. Among his works to enter the repertoire are pieces for piano, chamber music, two piano concertos, ballet music, two operas, and eight song cycles; he wrote no symphonies and only one religious work. Many of his works exist in two versions: a first, piano score and a later orchestration. Some of his piano music, such as Gaspard de la nuit (1908), is exceptionally difficult to play, and his complex orchestral works such as Daphnis et Chloé (1912) require skilful balance in performance.

Robert Schumann was a German composer and influential music critic. He is widely regarded as one of the greatest composers of the Romantic era. Schumann left the study of law, intending to pursue a career as a virtuoso pianist. He had been assured by his teacher Friedrich Wieck that he could become the finest pianist in Europe, but a hand injury ended this dream. Schumann then focused his musical energies on composing.
Schumann's published compositions were written exclusively for the piano until 1840; he later composed works for piano and orchestra; many Lieder (songs for voice and piano); four symphonies; an opera; and other orchestral, choral, and chamber works. Works such as Carnaval, Symphonic Studies, Kinderszenen, Kreisleriana, and the Fantasie in C are among his most famous. His writings about music appeared mostly in the Neue Zeitschrift für Musik (New Journal for Music), a Leipzig-based publication which he jointly founded.
In 1840, Schumann married Friedrich Wieck's daughter Clara, against the wishes of her father, following a long and acrimonious legal battle, which found in favour of Clara and Robert. Clara also composed music and had a considerable concert career as a pianist, the earnings from which, before her marriage, formed a substantial part of her father's fortune.
Schumann suffered from a mental disorder, first manifesting itself in 1833 as a severe melancholic depressive episode, which recurred several times alternating with phases of ‘exaltation’ and increasingly also delusional ideas of being poisoned or threatened with metallic items. After a suicide attempt in 1854, Schumann was admitted to a mental asylum, at his own request, in Endenich near Bonn. Diagnosed with "psychotic melancholia", Schumann died two years later in 1856 without having recovered from his mental illness.

Arnold Schoenberg was one of the most influential composers of the 20th century, but perhaps also one of the least listened to. Strikingly, Schoenberg was self-educated, even though his music is imbedded in complex music theory. It was Schoenberg who definitely departed from tonality and he developed the twelve tone technique. In this composition style, one has to use every twelve tones of the scale, before one can be repeated. The struggle to adhere to this dogma is clearly audible: his music is tense, hectic and particularly acute - and therefore at times not that accesible to occasional listeners.

Nevertheless, his music and his liberation of tonality had an enormous impact on all composers that came after him. Together with the music of his students Alban Berg and Anton Webern, his style is often referred to as the Second Viennese School, parallel to the First Viennese School of Mozart, Haydn and Beethoven, who, in a similar vein, changed the history of music for good.

His most performed works are his string sextet Verklärte Nacht, his five Orchestra pieces op. 16, and his opera Moses und Aron. The development of Schoenberg's music can be heard in his Five String Quartets in particular.