 Sometimes the quotation is done for the purposes of characterization, as in Puccini's use of "The Star-Spangled Banner" in reference to the American character Lieutenant Pinkerton in his opera "Madama Butterfly", or in Tchaikovsky's use of the Russian and French national anthems in the "1812 Overture", which depicted a battle between the Russian and French armies.Sometimes, there is no explicit characterization involved, as when Luciano Berio used brief quotes from Johann Sebastian Bach, Ludwig van Beethoven, Alban Berg, Pierre Boulez, Gustav Mahler, Claude Debussy, Paul Hindemith, Maurice Ravel, Arnold Schoenberg, Karlheinz Stockhausen, Richard Strauss, Igor Stravinsky, Anton Webern, and others in his "Sinfonia".Musical quotation is to be distinguished from variation, where a composer takes a theme (their own or another's) and writes variations on it.