Before founding Megadeth in 1983, Dave Mustaine was an original member of Metallica (his songs were recorded by them after his departure). With Megadeth, however, he pursued his own vision; equally inspired by heavy metal and punk, Mustaine and company released pioneering thrash-metal in the '80s and 1990s. All of their '90s albums debuted in the Top Ten. Over the years, through personnel changes and stylistic evolution towards a more melodic, accessible sound, Megadeth sold millions of records. They are so influential, that along with Metallica, Slayer and Anthrax, they are one of the "Big Four" in thrash metal history.