There's a really great story behind this song.The late great John Bonham was really good friends with George Harrison of The Beatles.By end of 1960s Led Zeppelin was well established band.George Harrison was once talking with Bonham and George told Bonham that the problem with Led Zeppelin is that you guys don't write ballads.John discussed this with his band.And the result was The Rain Song. So technically Beatles was responsible for this great Led Zep tune.