The Beatles’ “Yesterday” was one of the earliest signs of their rapid growth and maturity, and has since become one of their most beloved and enduring songs. The string-laden ballad, written by Paul McCartney, was recorded on June 14, 1965.

That day was, in fact, dominated by McCartney compositions. In the afternoon session, from 2:30-5:30PM, the Beatles banged out “I’ve Just Seen a Face” and “I’m Down,” the latter of which served as the b-side of “Help!” But it was during the three hours later that evening, from 7-10PM, that history was made.

The story of the writing of “Yesterday” is, by now, almost as famous as the actual song. Paul McCartney woke up one morning with it inside his head. Plucking it out at the piano at his bedside, he wondered where he had heard it before. “It was like a jazz melody,” he said in Anthology. “My dad used to know a lot of old jazz tunes. I thought maybe I’d just remembered it from the past.”

McCartney played it for friends to see if they knew the source. Once he realized it was his own creation, it was time for the words. Unable to come up with anything, he used the lines “Scrambled eggs / Oh, my baby, how I love your legs” to figure out the meter. Realizing it should be a one-word title, McCartney came up with “Yesterday.”

When McCartney presented it to the other Beatles, the other three members quickly discovered there was no place for them to contribute. Producer George Martin suggested adding strings, but McCartney originally balked. “Paul said, ‘I don’t want Mantovani,’” Martin revealed in Anthology. “I said, ‘What about a very small number of string players, a quartet?’”

Intrigued, the two then collaborated on the arrangement. The classically trained Martin wasn’t thrilled with two of McCartney’s suggestions, the seventh by the cello in the second verse and the high note held by the violin in the last verse. But he relented to the composer’s requests. “That was the way the process worked,” McCartney said. “He’d show me how to write the song correctly and I’d try to sabotage the correct method and move towards the way I like music – make it original. I still think that’s a good way to work.”

Watch the Beatles Perform 'Yesterday'

Recording the song, however, was far easier than writing it. McCartney did it in one take with his acoustic guitar, with the strings being overdubbed — also in one take — while the singer redid his vocal. The quartet, according to Mark Lewisohn's The Beatles Recording Sessions: The Official Abbey Road Studio Session Notes, 1962-1970, consisted of Tony Gilbert (violin), Sidney Sax (violin), Francisco Gabarra (cello) and Kenneth Essex (viola).

Even though McCartney is the only Beatle on it, there was never any serious talk about it being credited to him alone. In fact, it wasn’t released as a single in the U.K. “We were a little embarrassed about it; we were a rock 'n' roll band,” McCartney added.

Instead, it was buried as the second-to-last song on the second side of Help! But for all of Capitol’s mishandling of the Beatles’ catalog in the U.S., they saw this song's potential. "Yesterday" was issued as a single on Sept. 13, 1965. A month later, the tune went to No. 1, where it stayed for four weeks. In June 1966, it was essentially the title track to Capitol's Yesterday and Today LP.

The Beatles Bible says that a song that once “embarrassed” the group has since been recorded by more than 3,000 other artists.