<Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (April 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> Musical eras and their prevalent styles, forms and instruments seldom disappear at once; instead, features are replaced over time, until the old approach is simply felt as "old - fashioned". The Classical style did not "die" suddenly; rather, it gradually got phased out under the weight of changes . To give just one example, while it is generally stated that the Classical era stopped using the harpsichord in orchestras, this did not happen all of a sudden at the start of the Classical era in 1750 . Rather, orchestras slowly stopped using the harpsichord to play basso continuo until the practice was discontinued by the end of the 1700s . </P> <P> One crucial change was the shift towards harmonies centering on "flatward" keys: shifts in the subdominant direction . In the Classical style, major key was far more common than minor, chromaticism being moderated through the use of "sharpward" modulation (e.g., a piece in C major modulating to G major, D major, or A major, all of which are keys with more sharps). As well, sections in the minor mode were often used for contrast . Beginning with Mozart and Clementi, there began a creeping colonization of the subdominant region (the ii or IV chord, which in the key of C major would be the keys of d minor or F major). With Schubert, subdominant modulations flourished after being introduced in contexts in which earlier composers would have confined themselves to dominant shifts (modulations to the dominant chord, e.g., in the key of C major, modulating to G major). This introduced darker colors to music, strengthened the minor mode, and made structure harder to maintain . Beethoven contributed to this by his increasing use of the fourth as a consonance, and modal ambiguity--for example, the opening of the Symphony No. 9 in D minor . </P> <P> Franz Schubert, Carl Maria von Weber, and John Field are among the most prominent in this generation of "Proto - Romantics", along with the young Felix Mendelssohn . Their sense of form was strongly influenced by the Classical style . While they were not yet "learned" composers (imitating rules which were codified by others), they directly responded to works by Beethoven, Mozart, Clementi, and others, as they encountered them . The instrumental forces at their disposal in orchestras were also quite "Classical" in number and variety, permitting similarity with Classical works . </P>

Where was music performed in the classical period