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.
Foundations Forum
Foundations Forum was the first exclusively heavy metal music industry convention, held annually from 1988−1997 in Los Angeles. The convention was set up by Concrete Marketing who had in January 1988 created the first industry trade magazine for the heavy metal world - Foundations. Realizing there was little or no attention or focus on this growing market, and having seen the far reaching distribution of the trade magazine, they decided to put together an annual meeting, bringing together key industry personnel, vendors and artists (and in later forums fans as well) offering advice on surviving the industry, discussing the changing climate of the scene and business, and allowing people to network.