The formal separation of the Beatles is 50 years old this Sunday, a painful moment preceded by "many tensions" due to personal differences, creative conflicts, and the death in 1967 of their manager.

Although they initialed their dissolution in a document on December 29, 1974, John Lennon, Paul McCartney, George Harrison, and Ringo Starr had stopped working together between 1969 and 1970.

"They discovered that they were individualities and not just members of the band," Peter Doggett, author of the book "You Never Give Me Your Money: The Battle for the Soul of The Beatles," published in 2009 and focusing on the band's breakup, tells AFP.

That document, known as "The Beatles Agreement," has the date December 29, 1974, handwritten on it, with the signatures of the four band members. It allowed the quartet to structure their rights to song ownership and legal matters related to the breakup.

"The legal separation in December 1974 included an agreement whereby, under the terms of the original partnership, all of that money was divided equally among the four of them," adds Doggett.

Among the causes of the group's dissolution, pointed out by the authors who have written about the quartet, are personal differences, creative conflicts, and the death in 1967 of their manager Brian Epstein, without his replacement, Allen Klein, achieving unanimity in the quartet.

Profitable offers to return

"There were a lot of tensions between various group members," said Holly Tessler, head of the University of Liverpool's master's degree program on the Beatles.

Separation seemed the only possible way out, according to Doggett.

"It would have been a big mistake if they hadn't split up because the sense of unity that was their foundation between 1962 and 1969 was gone. They were beginning to see themselves as individuals outside of that association," he notes.

Tessler agrees that the estrangement between the four made another exit unfeasible.

"The fact that they never met despite numerous lucrative offers to do so speaks to how deeply rooted their tensions were," Tessler tells AFP.

Philip Norman, author of the 1981 book "Shout!: The True Story of The Beatles", also believes that it was difficult for the members to withstand the pressure they were under every day.

"It was often very unpleasant, very stressful and sometimes very scary to be a Beatle. And only the four of them understood that situation," Norman tells AFP.

After signing the December 29, 1974 paper, their lawyers soon thereafter finalized all legal aspects of the separation.

"It is quite possible that the dissolution was not made official in legal terms until early January. But as far as the Beatles were concerned, the agreement was made on December 29, when John signed and the date was added by hand to the typed document," Doggett explains.

There will never be others like it

The commercial network around the Beatles and the distribution among its members was not simple.

"With four different solo careers underway, the group's business affairs were very complicated to untangle. There were also considerable tax implications, as well as the issue of fulfilling their contract with Capitol Records that ran until 1976," Kenneth Womack, author of the book "Solid state: The story of Abbey Road and the end of The Beatles," published in 2013, tells AFP.

The Beatles broke up between 1969 and 1970 and officially disbanded on December 29, 1974, but their legacy lives on fifty years later.

"There will never be a 'new Beatles,' even though there has been a search for one since 1970. But the originals will always be a symbol of freedom, experimentation and optimism, which is in short supply in today's world. They symbolized all the incredible creative and social changes of the decade," sums up Doggett.

© Agence France-Presse. By Pablo San Román.