The classical era established the norms of structuring first movements and the standard
layouts of multi-movement works. There was a period of a wide variety of layouts and
formal structures within first movements which gradually became expected norms of
composition. The practice of Haydn and Mozart, and other composers, increasingly
influenced a generation which sought to exploit the possibilities offered by the forms
which Haydn and Mozart had established in their works. Theories on the layout of the
first movement gradually became more and more focussed on understanding the practice
of Haydn, Mozart and, later, Beethoven. Their works were studied, patterns and
exceptions to those patterns were identified, and the boundaries of acceptable or usual
practice were set by the understanding of their works. The sonata form, as described, is
identified with the norms of the classical period in music. Even before it was described it
it had become central to music-making, absorbing and altering other formal schemes.
The romantic era in music was to accept the centrality of this practice, codify the sonata
form explicitly and make instrumental music in this form central to concert and chamber
composition and practice, particularly for works which were meant to be regarded as
‘serious’ works of music. Various controversies in the nineteenth century would centre
on exactly what the implications of ‘development’ and sonata practice actually meant,
and what the rôle of the classical masters was in music. At the same time that the sonata
form was being codified by Czerny and others, the major and minor composers of the day,
ironically, were writing works that violated some of the principles of the codified sonata
form.
Sonata form has continued to be influential throughout the subsequent history of classical
music to the modern period. The twentieth century brought a wealth of scholarship that
sought to ground the theory of the sonata form on basic tonal laws. The twentieth
century would see a continued expansion of acceptable practice, leading to the
formulation of ideas that there existed a ‘sonata principle’ or ‘sonata idea’ which unified
works of the type, even if they did not explicitly meet the demands of the normative
description.
Sonata form and other musical forms
Sonata form shares characteristics with both binary form and ternary form. In terms of
key relationships it is very like binary form, with a first half moving from the home key
to the dominant and the second half moving back again. This is why sonata form is
sometimes called ‘compound binary form’. In other ways it is very like ternary form,
being divided into three sections, the first (exposition) of a particular character, the
second (development) in contrast to it, and the third section (recapitulation) of the same
character as the first.
The early binary sonatas by Domenico Scarlatti, of which there are more than 500,
provide excellent examples of the transition from binary form to sonata form. Among
those sonatas are numerous examples of the true sonata form being crafted into place.
During the eighteenth century many other composers like Scarlatti were discovering this
same musical form by experimenting at their keyboards harmonically and melodically.