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.
Christian metal
In the early 1980s, there were four notable Christian heavy metal groups: Messiah Prophet, Leviticus, Saint, and Stryper. Although it is debatable as to which band was formed first, the Orange County native glam metal group Stryper was the most popular one. Stryper was also the first band to identify as Christian metal. Stryper gained attention with their way of throwing Bibles to the audience at their concerts. In the beginning, mostly Christians went to Stryper's concerts but soon they reached non-Christian audience. In the 1980s, Christian metal bands closely followed the trends of mainstream heavy metal bands.