Sonata in B-flat Major for flute and harpsicord (H 543)

Carl Philipp Emanuel Bach (1714-1788) was a German composer, performer, and pedagogue who served as a critical bridge between the Baroque and Classical eras. The second surviving son of Johann Sebastian Bach, he was more famous than his father during his own lifetime and was widely regarded as the "Great Bach" by his contemporaries.
Born in Weimar to J.S. Bach and Maria Barbara Bach, he received his music education exclusively from his father, quickly establishing himself as a virtuoso on keyboard instruments, including the harpsichord and clavichord.
He studied law at the University of Leipzig (1731) and the University of Frankfurt an der Oder (1735), earning a degree in 1738, but ultimately chose to pursue a music career professionally.
For nearly 30 years, he served as the court harpsichordist for Frederick the Great of Prussia. During this time, he was known as the "Berlin Bach" and published his highly influential sets of "Prussian" and "Württemberg" sonatas. In 1768, he succeeded his godfather, Georg Philipp Telemann, as the Director of Music for Hamburg's five main churches. In this role, often called the "Hamburg Bach," he composed over 20 settings of the Passion and numerous choral works.
He was the leading representative of the "sensitive style," which focused on intimate, shifting emotions, sudden harmonic surprises, and expressive pauses. His work directly influenced Haydn, Mozart, and Beethoven. Mozart famously said of him, "He is the father, we are the children".
His "Essay on the True Art of Playing Keyboard Instruments" (1753) remains a primary source for 18th-century performance practice and was the first to advocate the standard use of the thumb in keyboard playing.