I'm not at all surprised at the distribution of knowledge. With an act as legendary as Led Zeppelin, I'm almost (pleasantly) surprised there are more than a few novices following. Hopefully this has the same kind of impact on them as it did all of us 'experts'.
But first, a little history lesson - and to give the background of all four members at once is way too long a post, I'm gonna split it in two so it's a little more digestible.
Jimmy Page's accolades run wide and deep - with the title of "Guitarist of the Year" 5 times in the 70s; claims such as "rock's greatest and most mysterious guitar hero", "the most captivating soloists the rock world has ever known", and "truly a guitar god"; always in the top 10 (usually top 3) rankings of various online and magazine polls of 'greatest guitarist of all time' - Page is responsible for some of the most memorable guitar sounds, riffs, and chords in rock. Guitarists that (according to wiki) were influenced by Page include include some pretty legendary guitarists themselves - Ace Frehley, Joe Satriani, James Hetfield, Kirk Hammett, Zakk Wylde, Yngwie Malmsteen, Joe Perry, Richie Sambora, Angus Young, Slash, Dave Mustaine, and Alex Lifeson. Helluva starter list.
Jimmy Page began playing guitar at the age of 13, and was largely self-taught. By the age of 17, Page caught the interest of Neil Christian playing a warm up gig one night, and was asked to join his band, Neil Christian and the Crusaders. Such was Page's first full-time gig. Making a name for himself, in just one year Page became a session musician at the Decca label, and his first recording with them would go on to be a #1 hit in the UK. Over the years, he would play on hundreds of sessions, contributing to dozens of very well known acts and their hits, including the Kinks' You Really Got Me, supporting Van Morrison completely in the studio (including Gloria), and even sat in on some sessions with The Who, contributing when Townshend couldn't cut playing the lead line (I Can't Explain). Page's time as a session musician greatly affected how he would shape Led Zeppelin, learning countless studio techniques.
By mid 1966, Page was approached by the Yardbirds (a second time ... he'd already been asked in '65 to join as a second guitarist to Clapton, but declined), both needing some new inspiration for their musical creativity. Page accepted (initially as the bassist), but during the ensuing tour, Beck had a sore throat one night and could not go on stage. Page was like a caged animal finally set free. His performance floored the rest of the band, and gave them a new lease on life. The Yardbirds had been fearing Beck's departure (the band would ultimately fire him), but now had nothing to fear with Page on the lead axe. The Yardbirds would officially disband in the spring of 1968, leaving Page (with Peter Grant) on the search to form a new band.
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John Paul Jones was the most reserved and least flamboyant of the band members, though no less influential as a bass player, keyboardist, and arranger. Counting Geddy Lee, Steve Harris, John Deacon and Gene Simmons having been influenced and inspired by Jones, his legacy is no less impressive than his three band mates.
Born as John Baldwin, Jones started playing piano at age six, learning from his father, who was a pianist and arranger for big bands in the 1940s and 1950s, His mother was also in the music business which allowed the family to often perform together touring around England. Jones joined his first band at 15, The Deltas. As early as 1962, Jones would remember people telling him he had to hear this guitarist playing for Neil Christian and the Crusaders, 'they've got this unbelievable guitarist'. And that is how he first heard of Jimmy Page - even before he'd heard of Jeff Beck or Eric Clapton. His career followed a similar path to Page's, also becoming a session musician with Decca, in 1964. It didn't take long for Jones to excel at arranging, along with his bass and keyboard playing. Jones too made contributions to well known acts/songs, notably Donovan's Sunshine Superman, and The Rolling Stones' She's a Rainbow.
In 1967, Jones was invited to play the sessions for The Yardbirds album Little Games, and it was here that he and Page made their lasting connection. They'd worked in sessions together in the past, but this was more of a 'band' setting (as Page was the only member of the Yardbirds allowed to participate in the studio during the recording of the album). In July of 1968, the two reconnected as Page was looking to form his own band. Jones also wanted to step out of the anonymity of being a session musician. Now all they needed was a singer and a drummer.
Plant and Bonham to come later tonight.