Testament (a.k.a. Legacy) is an American thrash metal band from California. Being one of the most influential American thrash metal bands, they were perhaps the most popular band of that scene to not break into the mainstream and see the success that the "Big Four of Thrash" did.
Testament was formed as Legacy in the San Francisco area in 1983 by guitarist Eric Peterson and his friend, Derrick Ramirez, also a guitarist, originally using the name Legacy. The band soon recruited bassist Greg Christian, drummer Mike Ronchette, and vocalist Steve Souza. Ramirez was subsequently replaced by young guitar prodigy Alex Skolnick, who had studied under the legendary bay-area guitarist Joe Satriani. The band released one self-titled 4 song demo in 1986. Ronchette left shortly after the recording and was replaced by Louie Clemente. Steve Souza subsequently left the band to join Exodus, and suggested that Chuck Billy should replace him on lead vocals. While recording their first album, the band was forced to change their name to Testament because another band held a trademark for the name "The Legacy".