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.
Death (metal band)
Death was an American death metal band from Orlando, Florida, founded in 1983 by guitarist and vocalist Chuck Schuldiner. Death is considered to be among the most influential bands in heavy metal and a pioneering force in the extreme metal subgenre of death metal. Their debut album, "Scream Bloody Gore", has been widely regarded as the first death metal record (although there is some divide amongst the genre's leading experts, as Possessed's debut album "Seven Churches" and Necrophagia's debut album "Season of the Dead" were released before).