Deep Purple are an English rock band formed in Hertford in 1968, being pioneers of heavy metal and modern hard rock, having been a progressive rock band, which changed to a heavier sound in 1970. Deep Purple, Led Zeppelin and Black Sabbath, have been described as the "unholy trinity of British hard rock and heavy metal in the early to mid-seventies". In the 1975 Guinness Book of World Records they were given as "the globe's loudest band" for their 1972 concert at London's Rainbow Theatre, having sold over 100 million albums worldwide. Deep Purple have had several line-up changes broken by an 8-year hiatus from 1976-1984, with earlier line-ups often being labelled Mark I, II, III and IV. Their 2nd, most successful line-up comprised Ian Gillan (vocals), Jon Lord (keyboards, backing vocals), Roger Glover (bass), Ian Paice (drums), and Ritchie Blackmore (guitar). This was active from 1969 to 1973, with later revivals between 1984 -1989, then from 1992 to 1993. The group was less successful between 1968 - 1969, with the line-up including Rod Evans (lead vocals) and Nick Simper (bass, backing vocals), from 1974 - 1976, with Tommy Bolin replacing Blackmore in 1975, the line-up including David Coverdale (lead vocals) and Glenn Hughes (bass, vocals), and between 1989 - 1992, when it included Joe Lynn Turner (vocals). The band's membership, including Ian Gillan, and guitarist Steve Morse from 1994, has been far more stable in recent years, although keyboardist Jon Lord's retirement from the band in 2002, being succeeded by Don Airey, left Ian Paice as the only original Deep Purple member still in the group. Deep Purple were ranked # 22 on VH1's Greatest Artists of Hard Rock programme, with a poll on British radio station Planet Rock having ranked them 5th of the "most influential bands ever". The band received the Legend Award at the 2008 World Music Awards. Deep Purple, as Blackmore, Lord, Paice, Gillan, Glover, Coverdale, Evans and Hughes, were inducted into the Rock and Roll Hall of Fame in 2016.