Also called Johann Ernst "of Eisenach" (or Weimar) so as not to confuse him with Sebastian's first cousin by the same name, this famous second cousin studied with Johann Sebastian as a student at the Thomasschule (ca. 1735) in Leipzig. As part of these studies Ernst copied twelve concerti by Vivaldi which Sebastian later adapted to the clavier. A lawyer by training and in his early career, Johann Ernst's musical skills were sufficient for him to change careers in 1748, becoming organist and colleague to his father, Johann Bernhard, in Eisenach. After his father's death Johann Ernst was appointed Kapellmeister of Sax Weimar. When the Eisenach chapel was dissolved, Johann Ernst continued to compose. His greatest work is considered to be the Passion oratorioO Seele, deren Sehnen (1764). Some of his chamber works were printed during his lifetime. Of the two cousins by the name of Johann Ernst, this man established the greater reputation as a musician.