Telemann had been musical director of the five most important churches in Hamburg, but upon his death on June 25, 1767, this post was left vacant.
Bach applied and was awarded the post in preference to three other candidates, including his half-brother Johann Christoph Friedrich.
Their degree of difficulty was such that they were clearly intended for extremely skilled musicians.
In contrast, later published keyboard works were written for and marketed towards home music-making by amateurs; these include six sonatas “for the use of women.” Bach continued, however, to write difficult sonatas, but these were almost never published.
Also as a result of the war, Bach joined the militia (although he never actually fought in a battle).
Bach made another attempt to transfer out of Berlin in 1767.
The book continued to be used into the nineteenth century, long after C. Nichelmann left the court, and Bach received a raise.
In 1756, the Seven Years’ War broke out, and musical life at court was greatly curtailed because Frederick II was usually off fighting.
Carl Philipp Emanuel hated his time there, although he was the catalyst for a remarkable encounter between the young king and C. E.’s father, the great Johann Sebastian, which led to the creation of J. Bach’s “The Musical Offering.” (There’s a fascinating and insightful book all about this meeting, Evening in the Palace of Reason by James R. But it also established the rationale for expressivity in music: "Since a musician cannot move others unless he himself is moved, he must of necessity feel all of the affects that he hopes to arouse in his listeners." That was something nobody had said before, and Haydn, Mozart and Beethoven took it to heart.
His first major post was in Berlin, as a musician in the court of Frederick the Great. For instance, keyboard players use their thumbs today because of the influence of this book.