German composer, organist, singing teacher, and writer on music. He studied law at the University of Leipzig, 1738-41, simultaneously studying music with J. S. Bach and later with Quantz in Berlin. He became a court composer to Frederick the Great in 1751 and in 1759 succeeded Graun as director of the royal opera. Highly regarded as an organist and as a singing teacher. He published an annotated translation of Tosi's treatise on singing (Anleitung zur Singekunst, Berlin, 1757), collaborated with C.P. E. Bach on the obituary of J. S. Bach, and helped to prepare the publication of Adlung's work on organs. Other writings include an article on melody (published in the Magazin der Musik 2 [1786]), pamphlets taking up the cause of Italian music against Marpurg's advocacy of French taste, and a biography of Graun. His own compositions include eleven Italian operas or other dramatic works produced in Potsdam and Berlin; German sacred oratorios and cantatas; many songs in the style of the First Berlin School; keyboard pieces; chorale preludes for organ.