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 genres
The term was first used in the middle of the 1980s and refers to two different but related styles: the first pioneered and largely practiced in North America with a harder sound similar to speed metal, and a later more widespread and popular style based in Europe (especially Germany, Finland, Italy and Scandinavia), Latin America (Argentina, Brazil) and Japan, with a lighter, more melodic sound and frequent use of keyboards. Examples of power metal bands include DragonForce, Blind Guardian, Helloween, Sonata Arctica, Angra, Sabaton, Stratovarius, Kamelot, and HammerFall.
Progressive metal is a fusion between progressive rock and heavy metal. It is one of heavy metal's more complex genres, due to its use of unusual and dynamic time signatures, long compositions, complex compositional structures, and skilled instrumental playing, where instrumental solos are detailed and extended. However, the latest age of progressive metal has favored rougher lyrics and lower-pitched riff sequences with high amounts of strumming. Vocals, if present, are melodic (though there are a few that utilise unclean vocals), and lyrics are often philosophical, spiritual, or political. Many bands of the genre were influenced by the progressive rock band Rush, who would often incorporate elements of heavy metal into their music. Examples of the genre include Queensrÿche, Dream Theater, Opeth, Tool, Fates Warning, Mastodon, Gojira and Pain of Salvation.