Stairway to Heaven was released by the band Led Zeppelin on their untitled album, commonly known as Led Zeppelin IV or
"All epic anthems must measure themselves against "Stairway to Heaven," the cornerstone of Led Zeppelin IV. Building from an acoustic intro that sounds positively Elizabethan, thanks to John Paul Jones' recorder solo and Plant's fanciful lyrics, it morphs into a Page solo that storms heaven's gate." 
(sometimes called "zoso") November, 1971. The song was written by band members Jimmy Page and Robert Plant in 1970. Page was improvising and Plant relates that spontaneously, "My hand was writing out the words, 'There's a lady who's sure, all that glitters is gold, and she's buying a stairway to heaven.' I just sat there and looked at them and almost leapt out of my seat." (Llewellyn, Sian, December, 1998. "Stairway to Heaven." Total Guitar, p.61-62)
It was recorded December, 1970 and was first performed live March 5, 1971, in Belfast, Northern Ireland. Although bassist John Paul Jones remembered the crowd as being unimpressed and bored with the song, Robert Plant had this to say: "I'm not saying the whole audience gave us a standing ovation - but there was this sizable standing ovation there. And I thought, 'This is incredible because no one's heard this number yet. This is the first time hearing it!' It obviously touched them, so I knew there was something with that one." (unable to verify source)
Although a few promotional copies of the single were released, the band would not give their permission for "Stairway to Heaven" to be released officially as a single. The song, clocking in at a little over eight minutes, would have to be edited to fit onto the 45rpm records of the 70's. Because no single was released, album sales of the untitled Led Zeppelin IV, on which the song first appeared, skyrocketed.
From The Rolling Stone:
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