Heavy metal music
Critics disagree over who can be thought of as the first heavy metal band. Most credit either Led Zeppelin or Black Sabbath, with American commentators tending to favour Led Zeppelin and British commentators tending to favour Black Sabbath, though many give equal credit to both. A few commentators—mainly American—argue for other groups including Iron Butterfly, Steppenwolf or Blue Cheer. Deep Purple, the third band in what is sometimes considered the "unholy trinity" of heavy metal (Black Sabbath, Led Zeppelin, and Deep Purple), despite being slightly older than Black Sabbath and Led Zeppelin, fluctuated between many rock styles until late 1969 when they took a heavy metal direction.
Heavy metal music
On the other side of the Atlantic, the trend-setting group was Grand Funk Railroad, described as "the most commercially successful American heavy-metal band from 1970 until they disbanded in 1976, [they] established the Seventies success formula: continuous touring". Other influential bands identified with metal emerged in the U.S., such as Sir Lord Baltimore ("Kingdom Come," 1970), Blue Öyster Cult ("Blue Öyster Cult", 1972), Aerosmith ("Aerosmith", 1973) and Kiss ("Kiss", 1974). Sir Lord Baltimore's 1970 debut album and both Humble Pie's debut and self-titled third album were all among the first albums to be described in print as "heavy metal", with "As Safe As Yesterday Is" being referred to by the term "heavy metal" in a 1970 review in "Rolling Stone" magazine. Various smaller bands from the U.S., U.K, and Continental Europe, including Bang, Josefus, Leaf Hound, Primeval, Hard Stuff, Truth and Janey, Dust, JPT Scare Band, Frijid Pink, Cactus, May Blitz, Captain Beyond, Toad, Granicus, Iron Claw, and Yesterday's Children, though lesser known outside of their respective scenes, proved to be greatly influential on the emerging metal movement. In Germany, Scorpions debuted with "Lonesome Crow" in 1972. Blackmore, who had emerged as a virtuoso soloist with Deep Purple's highly influential album "Machine Head" (1972), left the band in 1975 to form Rainbow with Ronnie James Dio, singer and bassist for blues rock band Elf and future vocalist for Black Sabbath and heavy metal band Dio. Rainbow with Ronnie James Dio would expand on the mystical and fantasy-based lyrics and themes sometimes found in heavy metal, pioneering both power metal and neoclassical metal. These bands also built audiences via constant touring and increasingly elaborate stage shows.