Editing History of sonata form (section)

== Classical era (ca 1750 – ca 1825) ==
[[File:CPEB by Löhr.jpg|thumb|Portrait of composer [[Carl Philipp Emanuel Bach|C.P.E. Bach]]]]
The older Italian sonata form differs considerably from the later sonata in the works of the [[First Viennese School|Viennese Classical masters]].<ref>{{cite book|last=Leichtentritt|first=Hugo|title=Musical form|url=https://archive.org/details/musicalform00leic|page=[https://archive.org/details/musicalform00leic/page/122 122]|year=1951|publisher=Harvard University Press}}</ref> Between the two main types, the older Italian and the more "modern" Viennese sonata, various transitional types are manifest in the middle of the 18th century, in the works of the [[Mannheim school|Mannheim composer]]s, [[Johann Stamitz]], [[Franz Xaver Richter]], C.P.E. Bach, and many others.

The crucial elements that led to the sonata form were the weakening of the difference between binary and [[ternary form]]; the shift of texture away from full [[polyphony]] (many voices in imitation) to homophony (a single dominant voice and supporting harmony); and the increasing reliance on juxtaposing different [[key (music)|keys]] and textures. As different key relationships took on a more and more specific meaning, the schematics of works altered. Devices such as the false [[reprise]] fell out of favor, while other patterns grew in importance.

Quite probably the most influential composer on the early development of sonata form was [[Carl Philipp Emanuel Bach|C.P.E. Bach]], a son of J.S. Bach. Taking the harmonic and voice-leading techniques that his father had developed, he applied them to the homophonic style – allowing dramatic shifts in key and mood, while maintaining an overall coherence. C.P.E. Bach was a decisive influence on Joseph Haydn. One of C.P.E. Bach's most lasting innovations was the shortening of the [[theme (music)|theme]] to a [[motif (music)|motif]], which could be shaped more dramatically in pursuit of [[musical development|development]]. By 1765, C.P.E. Bach's themes, rather than being long melodies, had taken on the style of themes used in sonata form: short, characteristic, and flexible. By linking the changes in the theme to the harmonic function of the section, C.P.E. Bach laid the groundwork that composers such as Haydn and Wolfgang Amadeus Mozart would exploit.

The practice of the great Classical masters, specifically Haydn and Mozart, forms the basis for the description of the sonata form. Their works served both as the model for the form, and as the source for new works conceived in the sonata form itself. Debates about sonata form therefore reference the practice of Haydn and Mozart extensively.

[[Joseph Haydn]] is thought of as "the Father of the [[Symphony]]" and "the Father of the [[String Quartet]]". He can also be thought of as the father of the sonata form as a means of structuring works. His string quartets and symphonies in particular display not merely the range of applications of the form, but also the way to exploit its dramatic potential. It is predominantly Haydn who created the transition to the [[musical development|development]] and the transition to the [[recapitulation (music)|recapitulation]], as moments of supreme tension and dramatic interest. It is also Haydn who enabled a more expansive contour for works, by making every aspect of the harmony of a work implicit in its main theme. This is no small innovation, in that it creates a homophonic analog to the polyphonic fugue – a seed of potential from which the composer could later germinate a range of different effects. Haydn's variety of dramatic effects and ability to create tension was remarked upon in his own time: his music was increasingly taken as the standard by which other practice might be judged.

Haydn's [[String Quartets, Op. 33 (Haydn)|set of string quartets, Op. 33]] gives the first examples of coordinated use of the resources of sonata form in characteristic fashion. The composer himself listed them as being written on completely new principles and marking the turning point in his technique.

Wolfgang Amadeus Mozart applied the large-scale ideas of Haydn to opera and the [[piano concerto]]. Mozart's fluidity with the creation of themes, and the dense network of motives and their parts give his work a surface polish which was remarked upon even by his professional rivals. Mozart favored sonata form and the sonata cycle. Most of his compositions were in sonata cycle. He explored every genre of his day and perfected them all.  By the end of his short life, Mozart had absorbed Haydn's technique and applied it to his own more elongated sense of theme, for example in the [[Prague Symphony]].