Having published a booklet on plagiarism for students, my thoughts have from time to time turned to plagiarism in music. By 'plagiarism' I’m not thinking of conscious quotations (e.g. from the Eroica Symphony in Strauss’ Metamorphosen) or variations on other composers’ themes. I know that we’re treading a fine line here, and perhaps 'plagiarism' is not the right word, as one will never encounter in music anything like the extensive and even verbatim appropriations of other people's words and ideas as we do in plagiarised writings. Nevertheless, there are times when the similarity between a musical theme and another by a different composer is so striking that we can't help but wonder. There's an old joke about Rossini sitting through an opera, and now and then, when a new aria appeared, he would doff his hat as if greeting someone. When asked what he was doing, he said, 'Oh, I'm just greeting an old friend!'
How widespread is musical plagiarism? In one of his Harvard lectures ('The Unanswered Question'), Leonard Bernstein once demonstrated how Wagner had ‘plagiarised’ from Berlioz's Romeo et Juliette in his Tristan und Isolde. Pretty ironic, considering how Bernstein himself seemed to have plagiarised from the slow movement of Beethoven's Emperor Concerto in 'Somewhere', and from Wagner's Redemption by Love theme (end of Gotterdammerung) in 'I have a love', both from West Side Story. Another example that springs to mind is the majestic horn theme marking the arrival on the summit in Strauss' Alpine Symphony, which seems to have been lifted from the climax of the slow movement of Bruch's Violin Concerto No.1 (played again by horns, but as a countermelody). But most of the instances of musical plagiarism that I’m aware of have come from movies and musicals, where presumably the composers are short on both time and talent.
I've put a few examples of what I would consider to be musical 'plagiarism' on the following webpage: http://lc.hkbu.edu.hk/staff/tonyhung/music. (The suspect passage is played first, followed by the presumed original.) I suppose the composer of My Fair Lady (Loewe) might say that he was only 'paying homage' to Suppe's The Beautiful Galatea, which was a kind of precursor to MFL (being a musical comedy based on the same Pygmalion legend). But I wonder what excuses the others had, especially Strauss?