Answer by taking a quote from the following article:

Deep Purple are an English rock band formed in Hertford in 1968. The band is considered to be among the pioneers of heavy metal and modern hard rock, although their musical approach changed over the years. Originally formed as a progressive rock band, the band shifted to a heavier sound in 1970. Deep Purple, together with Led Zeppelin and Black Sabbath, have been referred to as the "unholy trinity of British hard rock and heavy metal in the early to mid-seventies".

In 1967, former Searchers drummer Chris Curtis contacted London businessman Tony Edwards, in the hope that he would manage a new group he was putting together, to be called Roundabout. Curtis' vision was a "supergroup" where the band members would get on and off, like a musical roundabout. Impressed with the plan, Edwards agreed to finance the venture with his two business partners John Coletta and Ron Hire, who comprised Hire-Edwards-Coletta Enterprises (HEC).  The first recruit to the band was the classically trained Hammond organ player Jon Lord, Curtis' flatmate who had most notably played with the Artwoods (led by Art Wood, brother of future Rolling Stones guitarist Ronnie Wood, and including Keef Hartley). Lord was then performing in a backing band for the vocal group The Flower Pot Men (formerly known as the Ivy League), along with bassist Nick Simper and drummer Carlo Little. Simper had previously been in Johnny Kidd and the Pirates and survived the 1966 car crash that killed Kidd. Lord put the two on alert that he'd been recruited for the Roundabout project, after which Simper and Little suggested guitarist Ritchie Blackmore, whom Lord had never met. Simper had known Blackmore since the early 1960s when his first band, the Renegades, debuted around the same time as one of Blackmore's early bands, the Dominators.  HEC persuaded Blackmore to return from Hamburg to audition for the new group. Blackmore was making a name for himself as a studio session guitarist, and had also been a member of the Outlaws, Screaming Lord Sutch, and Neil Christian. Curtis' erratic behaviour and lifestyle, fuelled by LSD use, caused a sudden disinterest in the project he had started, forcing HEC to dismiss him from Roundabout. But HEC was now intrigued with the possibilities Lord and Blackmore brought, while Lord and Blackmore were also keen to continue. The two carried on, recruiting additional members and keeping Tony Edwards as their manager. Lord convinced Simper to join for good, but left Carlo Little behind in favour of drummer Bobby Woodman.  In March 1968, Lord, Blackmore, Simper and Woodman moved into Deeves Hall, a country house in South Mimms, Hertfordshire. The band would live, write and rehearse at Deeves Hall, which was fully kitted out with the latest Marshall amplification. According to Simper, "dozens" of singers were auditioned (including Rod Stewart and Woodman's friend Dave Curtiss)until the group heard Rod Evans of the club band The Maze, and thought his voice fit their style well. Tagging along with Evans was his band's drummer, Ian Paice. Blackmore had seen Paice on tour with The Maze in Germany in 1966, and had been impressed by the 18-year-old's drumming. The band hastily arranged an audition for Paice, given that Woodman was vocally unhappy with the direction of the band's music. Both Paice and Evans won their respective jobs, and the line-up was complete.  During a brief tour of Denmark and Sweden in April, in which they were still billed as Roundabout, Blackmore suggested a new name: "Deep Purple", named after his grandmother's favourite song. The group had resolved to choose a name after everyone had posted one on a board in rehearsal. Second to Deep Purple was "Concrete God", which the band thought was too harsh to take on.

Who were the members of the band?
The first recruit to the band was the classically trained Hammond organ player Jon Lord, Curtis' flatmate