The Maurerische Trauermusik (Masonic Funeral Music) in C minor, K. 477 (K. 479a), is an orchestral work composed by Wolfgang Amadeus Mozart in 1785 in his capacity as a member of the Freemasons. Mozart's own entry into his catalogue under the heading "July 1785" must be considered in error; he most likely forgot to enter a new heading for November. It was performed during a Masonic funeral service held on 17 November 1785 in memory of two of Mozart's Masonic brethren, Duke Georg August of Mecklenburg-Strelitz and Count Franz Esterházy von Galántha, members of the Viennese aristocracy.
The work uses the Gregorian chant psalm-tone, tonus peregrinus. The work is scored for strings; woodwind instruments including two oboes, a clarinet, three basset horns and a contrabassoon; and two horns. The basset horn parts were written for fellow Freemasons Anton David and Vincent Springer.