Famously, any Beatles song written by either John Lennon or Paul McCartney was listed as a “Lennon-McCartney” composition, a tradition that was maintained throughout the band’s existence. The decision was made very early on, back when the pair were taking their first steps to becoming songwriters. “We always had that thing that our names would go on songs even if we didn’t write them. It was never a legal deal between Paul and me, just an agreement to put both our names on our songs,” said Lennon in “All We Are Saying,” one of the final interviews he gave in his lifetime.

One exception was their debut album, “Please Please Me.” The initial pressing credited McCartney-Lennon for the original songs on the album, reports Rolling Stone, but Lennon “pulled some strings” to get that changed. “I wanted it to be McCartney-Lennon, but John had the stronger personality and I think he fixed things …,” said McCartney in his biography, “Many Years From Now” (via Rolling Stone). “I remember going to a meeting and being told, ‘We think you should credit the songs to Lennon-McCartney. … Lennon-McCartney sounds better, it has a better ring. …’ I had to say, ‘All right, sod it.'” 

Even in 1969, when The Beatles were starting to record and perform with other artists, the pull of the old co-credit was still strong. Lennon’s anti-war anthem “Give Peace A Chance” was actually written in collaboration with Lennon’s wife Yoko Ono, but was still credited to Lennon-McCartney on the record. Old habits die hard.

More recently, McCartney received some criticism for attempting to change the iconic credit, and to have songs he penned alone listed as “McCartney-Lennon” compositions on his later solo and live albums (per The Guardian), but McCartney eventually backed down: “I’m happy with the way it is and always has been. Lennon and McCartney is still the rock ‘n’ roll trademark I’m proud to be a part of – in the order it has always been.”

Businesspeople will tell you that competition can be productive, and in the music business, it’s no different — at least if the relationship between Paul McCartney and John Lennon is anything to go by. As well as the “eyeball to eyeball” style of songwriting that created some of The Beatles’ most famous early recordings, the Lennon-McCartney songwriting partnership often operated separately — even in the early days — with one writer bringing the majority of a song to the other for critique, edits, and additions. Even when they were apart, they were working under the other’s influence. “John needed Paul’s attention to detail and persistence. Paul needed John’s anarchic, lateral thinking,” said Lennon’s first wife, Cynthia, according to The Atlantic.

Per Slate, producer George Martin described their relationship as: “two people pulling on a rope, smiling at each other and pulling all the time with all their might. The tension between the two of them made for the bond.” According to the book “Conversations with McCartney” (per OverSixty), such rivalry was “necessary” for the two creatives; even a decade after the Beatles broke-up, Lennon was inspired to return to music after a five-year hiatus after hearing a song by McCartney that impressed him.

“I’m still very competitive,” McCartney told GQ in 2018, whose productivity and collaborative impulses — he has worked with everyone from Kayne West to John Homme — remain undimmed.

The year 1967 was a transformative one for The Beatles, the decisive period in which the friendly rivalry that propelled the Lennon-McCartney songwriting partnership to the highest possible critical and commercial heights began to disintegrate. May that year saw the release of “Sgt. Pepper’s Lonely Hearts Club Band,” which critics including Rolling Stone‘s Kurt Loder have argued is, if not definitively the best Beatles release, certainly their most iconic and representative work, the perfect soundtrack to 1967’s Summer of Love and a release that has become indelibly linked to the ’60s counterculture.

But “Sgt. Pepper” also signaled the moment Lennon and McCartney’s interests started to diverge, and the power struggle between the two, which would complicate final years of the band, began. As Rolling Stone notes, the concept album was primarily McCartney’s idea, whose role in the group was expanding as Lennon found himself in crisis, withdrawing from the world amid the last turbulent months of his unhappy first marriage. “I was still in a real big depression in ‘Pepper,’ and I know Paul wasn’t at that time. He was feeling full of confidence … I was going through murder,” Lennon commented.

Though the “Sgt. Pepper” tune “A Day In The Life” represents one of the greatest successes of the Lennon-McCartney partnership, the song is emblematic of their increasingly separate songwriting, being a combination of two different compositions. As time went on, it became obvious that the “eyeball to eyeball” songwriting of the early sixties would never be revisited.

While Paul McCartney’s announcement that The Beatles were no more certainly meant he attracted plenty of ire from fans and critics alike, it managed to enrage John Lennon in that it inherently suggested that McCartney was the band’s de facto leader. “I started the band, I disbanded it. It’s as simple as that,” declared Lennon (per the Independent), who was keen to broadcast the fact he had kept his end of the bargain and kept quiet about the band’s break-up for the sake of future releases.

But the war of words didn’t just occur through the press — it was also waged on wax. In 1971, McCartney released “Ram,” his second album with his wife, Linda, containing the song “Too Many People,” which Lennon interpreted as a swipe against him and Yoko Ono. Lennon hit back with the brutal “How Do You Sleep?” which features the line: “Those freaks was right when they said you was dead,” a reference to the longstanding urban myth that McCartney died in the early ’60s and had been replaced by an imposter.

For many, the disunity that characterized the post-Beatles relationship was symbolic of the end of the ’60s counterculture, something that Lennon himself noted in his 1970 Rolling Stone interview: “I don’t believe in it. The dream is over. I’m not just talking about the Beatles, I’m talking about the generation thing. It’s over.”

The only record on which John Lennon and Paul McCartney can be heard playing together after the dissolution of The Beatles is a bootleg: the poorly received “A Toot and a Snore in ’74,” a recording of a drug-fueled jam session; Pitchfork recently called the record “atrocious.”

But the fact that the two most bitterly at odds former Beatles were in the same room and finally making music together again — however fragmentary and chaotic the results — is testament to one thing: that by the mid-’70s the animosity between Lennon and McCartney that had fueled their feud for so long was finally beginning to dissipate. In interviews from around 1974 and 1975 (via YouTube), Lennon was relaxed enough about his relationship with McCartney to openly discuss the idea of a Beatles reunion, even admitting that he would “go along with it” if someone else organized it.

Although Lennon and McCartney never did work together again, it wasn’t a conscious decision — rather, the chance just never arose. Lennon effectively retired from music for five years in 1975 to care for his newborn son, Sean, while McCartney claimed it was “pot and politics” that meant he was unable to reconnect fully with his erstwhile songwriting partner in his final years, per Ultimate Classic Rock, as he was banned from entering America due to drug offenses, while Lennon and his young family were splitting their time between Los Angeles and New York.