Wikipedia describes how Paul McCartney dreamed the melody to “Yesterday” and then set it to nonsense lyrics:<\/p>\n
According to biographers of McCartney and the Beatles, McCartney composed the entire melody in a dream one night in his room at the Wimpole Street home of his then girlfriend Jane Asher and her family. Upon waking, he hurried to a piano and played the tune to avoid forgetting it.<\/p>\n
McCartney’s initial concern was that he had subconsciously plagiarised someone else’s work. As he put it, “For about a month I went round to people in the music business and asked them whether they had ever heard it before. Eventually it became like handing something in to the police. I thought if no-one claimed it after a few weeks then I could have it.”<\/p>\n
Upon being convinced that he had not robbed anyone of his melody, McCartney began writing lyrics to suit it. As Lennon and McCartney were known to do at the time, a substitute working lyric, titled “Scrambled Eggs” (the working opening verse was “Scrambled Eggs\/Oh, my baby how I love your legs”), was used for the song until something more suitable was written.<\/p>\n
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McCartney said the breakthrough with the lyrics came during a trip to Portugal in May 1965:<\/p>\n
“I remember mulling over the tune ‘Yesterday’, and suddenly getting these little one-word openings to the verse. I started to develop the idea … da-da da, yes-ter-day, sud-den-ly, fun-il-ly, mer-il-ly and Yes-ter-day, that’s good. All my troubles seemed so far away. It’s easy to rhyme those a’s: say, nay, today, away, play, stay, there’s a lot of rhymes and those fall in quite easily, so I gradually pieced it together from that journey. Sud-den-ly, and ‘b’ again, another easy rhyme: e, me, tree, flea, we, and I had the basis of it.”<\/p><\/blockquote>\n