linguistic:translation, information:extraction
1775–1790

Haydn, having worked for over a decade as the music director for a prince, had far more resources and scope for composing than most other composers. His position also gave him the ability to shape the forces that would play his music, as he could select skilled musicians. This opportunity was not wasted, as Haydn, beginning quite early on his career, sought to press forward the technique of building and developing ideas in his music. His next important breakthrough was in the Opus 33 string quartets (1781), in which the melodic and the harmonic roles segue among the instruments: it is often momentarily unclear what is melody and what is harmony. This changes the way the ensemble works its way between dramatic moments of transition and climactic sections: the music flows smoothly and without obvious interruption. He then took this integrated style and began applying it to orchestral and vocal music.

Haydn's gift to music was a way of composing, a way of structuring works, which was at the same time in accord with the governing aesthetic of the new style. However, a younger contemporary, Wolfgang Amadeus Mozart, brought his genius to Haydn's ideas and applied them to two of the major genres of the day: opera, and the virtuoso concerto. Whereas Haydn spent much of his working life as a court composer, Mozart wanted public success in the concert life of cities, playing for the general public. This meant he needed to write operas and write and perform virtuoso pieces. Haydn was not a virtuoso at the international touring level; nor was he seeking to create operatic works that could play for many nights in front of a large audience. Mozart wanted to achieve both. Moreover, Mozart also had a taste for more chromatic chords (and greater contrasts in harmonic language generally), a greater love for creating a welter of melodies in a single work, and a more Italianate sensibility in music as a whole. He found, in Haydn's music and later in his study of the polyphony of J.S. Bach, the means to discipline and enrich his artistic gifts.

Mozart rapidly came to the attention of Haydn, who hailed the new composer, studied his works, and considered the younger man his only true peer in music. In Mozart, Haydn found a greater range of instrumentation, dramatic effect and melodic resource. The learning relationship moved in both directions. Mozart also had a great respect for the older, more experienced composer, and sought to learn from him.

Mozart's arrival in Vienna in 1780 brought an acceleration in the development of the Classical style. There, Mozart absorbed the fusion of Italianate brilliance and Germanic cohesiveness that had been brewing for the previous 20 years. His own taste for flashy brilliances, rhythmically complex melodies and figures, long cantilena melodies, and virtuoso flourishes was merged with an appreciation for formal coherence and internal connectedness. It is at this point that war and economic inflation halted a trend to larger orchestras and forced the disbanding or reduction of many theater orchestras. This pressed the Classical style inwards: toward seeking greater ensemble and technical challenges—for example, scattering the melody across woodwinds, or using a melody harmonized in thirds. This process placed a premium on small ensemble music, called chamber music. It also led to a trend for more public performance, giving a further boost to the string quartet and other small ensemble groupings.

It was during this decade that public taste began, increasingly, to recognize that Haydn and Mozart had reached a high standard of composition. By the time Mozart arrived at age 25, in 1781, the dominant styles of Vienna were recognizably connected to the emergence in the 1750s of the early Classical style. By the end of the 1780s, changes in performance practice, the relative standing of instrumental and vocal music, technical demands on musicians, and stylistic unity had become established in the composers who imitated Mozart and Haydn. During this decade Mozart composed his most famous operas, his six late symphonies that helped to redefine the genre, and a string of piano concerti that still stand at the pinnacle of these forms.

One composer who was influential in spreading the more serious style that Mozart and Haydn had formed is Muzio Clementi, a gifted virtuoso pianist who tied with Mozart in a musical "duel" before the emperor in which they each improvised on the piano and performed their compositions. Clementi's sonatas for the piano circulated widely, and he became the most successful composer in London during the 1780s. Also in London at this time was Jan Ladislav Dussek, who, like Clementi, encouraged piano makers to extend the range and other features of their instruments, and then fully exploited the newly opened up possibilities. The importance of London in the Classical period is often overlooked, but it served as the home to the Broadwood's factory for piano manufacturing and as the base for composers who, while less notable than the "Vienna School", had a decisive influence on what came later. They were composers of many fine works, notable in their own right. London's taste for virtuosity may well have encouraged the complex passage work and extended statements on tonic and dominant.