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 fashion
Distinct aspects of heavy metal fashion can be credited to various bands, but the band that takes the most credit for revolutionizing the look was Judas Priest, primarily with its singer, Rob Halford. Halford wore a leather costume on stage as early as 1978 to coincide with the promotion for the "Killing Machine" ("Hell Bent for Leather" in the USA) album. In a 1998 interview, Halford described the leather subculture as the inspiration for this look. Halford may have been the one to popularize leather but K.K. Downing wanted a look that suited the music they were creating. Downing started wearing studded leather outfits on stage. Soon, the rest of the band followed. An example of this can be seen from live concert recordings from 1978. Downing is the only one on stage appearing with black studded leather jacket.