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.
List of speed metal bands
This is a list of speed metal bands. Speed metal is a subgenre of heavy metal music that originated in the late 1970s from NWOBHM and hardcore punk roots. It is described by AllMusic as "extremely fast, abrasive, and technically demanding" music.Their 1974 song "Stone Cold Crazy" is mentioned in Wikipedia article as first Speed metal song.