The appropriation of "classical" music by heavy metal typically includes the influence of Baroque, Romantic, and Modernist composers such as Johann Sebastian Bach, Niccolò Paganini, Richard Wagner, and Ludwig van Beethoven. In the 1980s, heavy metal appropriated much of its speed and technique from early eighteenth century "classical" influences. For instance, classically-inspired guitarist Yngwie Malmsteen's technical prowess inspired a myriad of neo-classical players including Michael Romeo, Michael Angelo Batio, and Tony MacAlpine.
Several music experts and metal musicians have noted the role of the tritone in heavy metal,[4] a dissonant interval comprising a root note and an augmented fourth/diminished fifth, e.g., C and F sharp, which ostensibly results in a "heavy," "evil" sound, so much so that its use was supposedly banned in medieval composition as Diabolus in Musica ("the devil in music"). The evocative tritone, which was exploited by Romantic composers and is definitive to the blues scale, is part of metal's heritage, and fundamental to its solos and riffs, as in the beginning of the eponymous Black Sabbath CD.
The late Baroque era of Western music was also frequently interpreted through a gothic lens. For example, "Mr. Crowley," (1981) by Ozzy Osbourne and guitarist Randy Rhoads, uses both a pipe organ-like synthesizer and Baroque-inspired guitar solos to create a particular mood for Osbourne's lyrics concerning the occultist Aleister Crowley. For the introduction to 1982s "Diary of a Madman," Rhoads borrowed heavily from Cuban classical guitar composer Leo Brouwer's "Etude #6." Like many other metal guitarists in the 1980s, Rhoads quite earnestly took up the "learned" study of musical theory and helped to solidify the minor industry of guitar pedagogy magazines (including Guitar for the Practicing Musician) that grew during the decade. In most instances, however, metal musicians who borrowed the technique and rhetoric of art music were not attempting to "be" classical musicians.
The Encarta encyclopedia states about the composer Johann Sebastian Bach that "when a text was associated with the music, Bach could write musical equivalents of verbal ideas." Progressive rock bands such as Emerson, Lake & Palmer and the band Yes had already explored this dynamic before heavy metal evolved. As heavy metal uses apocalyptic themes and images of power and darkness, the ability to successfully translate verbal ideas into music is often seen as critical to its authenticity and credibility. An example of this is the album Powerslave by Iron Maiden.[5] The cover is of a dramatic Egyptian scene and many of the songs on the album have subject matter requiring a sound suggestive of life and death, including a song titled "The Rime of the Ancient Mariner," based on the poem by Samuel Taylor Coleridge. Iron Maiden bassist Steve Harris has cited progressive rock bands[6] such as Rush and Yes as influences, and it should be noted that the 1977 Rush album entitled A Farewell to Kings features the eleven-minute "Xanadu," also inspired by Coleridge and pre-dating the Iron Maiden composition by several years begining of metal
