August Wilhelm Julius Rietz (28 December 1812, Berlin – 12 September 1877,[1] Dresden) was a German composer, conductor and cellist. He was a teacher among whose students were Woldemar Bargiel,[2] Salomon Jadassohn and Arthur Sullivan.[3] He also edited many works by Felix Mendelssohn for publication.
He studied the cello under Schmidt, Bernhard Romberg, and Gans. At 16, he joined the orchestra of the Königstädter Theater, for which he wrote the music to Holtei's play Lorbeerbaum und Bettelstab. In 1834, he was appointed assistant conductor at the Düsseldorf Opera under Mendelssohn, whom he succeeded the following year. In 1847, he was called to Leipzig as theatre kapellmeister and conductor of the Singakademie. In 1848, he succeeded Mendelssohn as conductor of the Gewandhaus concerts and as teacher of composition at the Conservatory. He was called to Dresden in 1860 to succeed Reissiger as court kapellmeister. Here he conducted the opera and afterwards undertook the direction of the royal conservatory. He died at Dresden.