Roots of Petra

Louis Andrew Grammatico, known professionally as Lou Gramm, is an American singer and songwriter. He is best known as co-founder and original frontman of the rock band Foreigner from 1976 to 1990 and again from 1992 to 2003, during which time the band had numerous successful albums and singles.

Lynyrd Skynyrd is an American rock band formed in Jacksonville, Florida, in 1964. The group originally formed as My Backyard and comprised Ronnie Van Zant (vocals), Gary Rossington (guitar), Allen Collins (guitar), Larry Junstrom (bass), and Bob Burns (drums). The band spent four years touring small venues under various names and with several lineup changes before deciding on "Lynyrd Skynyrd" in 1968. The band released its first album, (Pronounced 'Lĕh-'nérd 'Skin-'nérd), in 1973. By then, they had settled on a lineup that included bassist Leon Wilkeson, keyboardist Billy Powell, and guitarist Ed King. Burns left and was replaced by Artimus Pyle in 1974. King left in 1975 and was replaced by Steve Gaines in 1976. At the height of their fame in the 1970s, the band popularized the Southern rock genre with songs such as "Sweet Home Alabama" and "Free Bird". After releasing five studio albums and one live album, the band's career was abruptly halted on October 20, 1977, when their chartered airplane crashed, killing Van Zant, Steve Gaines, and backup singer Cassie Gaines, and seriously injuring the rest of the band.

Def Leppard are an English rock band formed in Sheffield in 1976. Since 1992, the band has consisted of Rick Savage, Joe Elliott, Rick Allen (drums), Phil Collen, and Vivian Campbell. They established themselves as part of the new wave of British heavy metal of the early 1980s.

Boston is an American rock band formed in 1975 in Boston, Massachusetts, by chief songwriter and composer Tom Scholz. The band's core members included multi-instrumentalist Scholz and lead vocalist Brad Delp, who remained the only constant members from 1975 to 1990, and from 1994 until Delp's suicide in 2007. Other musicians and members of the band varied largely across the group's lineup history.