Wolfgang Amadeus Mozart's Horn Concerto No. 3 in E-flat major, K. 447, was completed between 1784 and 1787, during the Vienna Period.

The Köchel catalogue is a chronological catalogue of compositions by Wolfgang Amadeus Mozart, originally created by Ludwig Ritter von Köchel, in which the entries are abbreviated K. or KV. Its numbers reflect the ongoing task of compiling the chronology of Mozart's works, and provide a shorthand reference to the compositions.