Heavy Metal music was only developed in the early 1960's.
 as 'classical music'" has been a major influence on heavy metal since the genre's earliest days, and that metal's "most influential musicians have been guitar players who have also studied classical music
 With roots in blues rock, psychedelic rock and acid rock, heavy metal bands developed a thick, monumental sound characterized by distorted guitars, extended guitar solos, emphatic beats and loudness

