Black Sabbath

Historical context

Birmingham band that forged heavy metal's down-tuned riffs, occult imagery, and working-class dread out of blues-rock wreckage. Invented the harmonic and thematic vocabulary metal still expands; without Sabbath's tritone gravity, later thrash and doom lack a parent. Factory-town noise and wartime bomb sites around Birmingham fed the band's sense that heaviness was environment, not costume.