Although Proto-doom is not properly a musical subgenre of doom metal, it is used to designate to the precursory bands of the characteristic sound that arose in the middle of 70´s and that is characterized by the slow and heavy rates. Bands like Iron Butterfly, Blue Cheer, Black Widow or Deep Purple in some of its songs like " In-To-Gadda-Give; , " Summertime Blues" or " Smoke on the Water" , they are considered like bands Proto Doom by the contributions in this sense. Nevertheless the major representing of proto doom, and considered angular stone of doom metal, is without doubt Black Sabbath. Although this band is considered a classic band of heavy pure metal and not a traditional band doom properly, their so coarse contributions to the diverse subgenera of heavy metal give to an essential place in the origin of doom metal him: their contributions to riffs of blues in the style of Cream and Jimi Hendrix (as well as of the bands before mentioned), but acclimated dismally, with malevolent and unfortunate dyes turn, them into the indispensable pioneers so that bands as Pentagram or Candlemass you would contruyeran the particular sound of the traditional doom in the middle of 70' s and 80' s.