Black Sabbath is credited with creating heavy metal. The success of their first two albums - Black Sabbath and Paranoid - marked a paradigm shift in the world of rock. Not until Black Sabbath upended the music scene did the term "heavy metal" enter the popular vocabulary to describe the denser, more thunderous offshoot of rock over which they presided. With their riff-based songs, extreme volume, and dark, demonic subject matter, Black Sabbath embodied key aspects of the heavy-metal aesthetic. Yet in their own words, they saw themselves as a "heavy underground" band. That term denoted both the intensity of their music and the network of fans who found them long before critics and the music industry took notice.
The response to Sabbath’s first two albums was instantaneous. Black Sabbath reached No. 8 in Britain and exhibited staying power in America, hanging on the charts for 65 weeks. Paranoid repeated the feat, peaking at No. 12 in the U.S. and charting for 70 weeks; while reaching No. 1 in the U.K. in a 27 week run. Both albums were certified gold within a year of release. Black Sabbath became an indefatigable road band, touring constantly and playing many of the early-70s rock festivals.
All of the roadwork improved them as musicians and songwriters, and their next two albums - Master of Reality (1971) and Vol. 4 (1972) - exhibited enhanced range and ambition. The group even threw in some notable changes of pace - such as the ballads “Solitude” and “Changes” and the instrumentals “Orchid” and “Laguna Sunrise” - to create more of a play of light and shadows. Those albums also contained their share of crunching Sabbath classics as well, such as “Children of the Grave” and “After Forever” (from Master of Reality) and “Snowblind” and “Supernaut” (from Vol. 4).