Sonata in A major, Opus 120, was written by Franz Schubert in 1819. The sonata was chosen for this study because of its proximity to the middle of the span of time in which Schubert wrote his piano sonatas. His first piano sonata was written in 1815 and the last in 1828. Since no sonatas were written in either 1821 or 1822, the years in the middle of this span, the sonata written in 1819 was chosen.

The purpose of this study is to show how standards of pitch became a matter of importance in musical performance. The existence of innumerable varieties of pitches was not an actual handicap in a time when voices were accompanied by only one instrument, or when a singer accompanied himself. But when instruments began to be used with the church organ, and ensembles were formed to play in the royal courts, a standard pitch was found to be desirable. Many factors were involved in the adjustments of pitch as small ensembles evolved into the military band and the symphony orchestra. An attempt will be made to show how many of the standards were derived, and what long lasting effects they had.