Overture

 Overture (from French ouverture, lit. "opening") in music was originally the instrumental introduction to a ballet, opera, or oratorio in the 17th century. During the early Romantic era, composers such as Beethoven and Mendelssohn composed overtures which were independent, self-existing instrumental, programmatic works that presaged genres such as the symphonic poem. These were "at first undoubtedly intended to be played at the head of a programme".