LONDON.- No one seemed to know what had happened to one of the most important bass guitars in music history, though in the decades since it went missing, there had been some dramatic rumors.

Was the Höfner violin bass, which had accompanied Paul McCartney and the Beatles to worldwide fame, tucked away in a private collection? Had it been secretly shipped to a wealthy fan in Japan?

It turned out the bass was passing time in a more unassuming locale: the loft of a family home in East Sussex, England. The family reported the guitar in late September after a couple of journalists and a guitar expert started a new campaign looking for it in 2023, more than 50 years after it was last seen.

The guitar, which has been authenticated by its manufacturer, has been returned to McCartney, according to a statement posted on his website Thursday. “Paul is incredibly grateful to all those involved,” it said.

It was the denouement to an enduring mystery that had gripped Beatles fans, including one group who pooled their skills to help find it.

‘It Started Beatlemania’

The Höfner 500/1 guitar is a precious part of Beatles lore. It can be heard on recordings of hit songs including “Love Me Do,” “She Loves You” and “Twist and Shout.”

After becoming the band’s bassist, McCartney desperately needed a bass guitar and bought the instrument in a music store in Hamburg, Germany, in 1961.

“I got my Violin Bass at the Steinway shop in the town center,” he recalled in a 1993 interview with Guitar Magazine. It cost the equivalent of 30 pounds — cheap enough for him to afford. “And once I bought it, I fell in love with it,” he said. “For a light, dinky little bass, it has a very rich sound.”

As the Fab Four found a whirlwind of fame, McCartney played the Höfner through hundreds of the gigs, including early concerts at the Cavern Club in Liverpool, England, where the Beatles met their future manager, Brian Epstein, and for the recordings of the band’s first two albums.

One of the last sightings of the bass was in London in 1969, in footage of the band writing their album “Let It Be.” Sometime after that, it disappeared.

Efforts to locate the bass had stalled until last September, when two journalists and a Höfner expert revived the search and appealed to the public for tips.

“It’s an iconic instrument,” said Nick Wass, a semiretired consultant for Höfner who has worked with McCartney. “It started Beatlemania.”

Among the hundreds of responses they received were some promising clues, said Scott Jones, a journalist who worked on the project with his wife, Naomi Jones.

A sound engineer who had worked with McCartney remembered that the guitar had been left in the back of a van in 1972 and that thieves had then broken in. Another tip, Scott Jones said, suggested that the guitar had been stolen in the neighborhood and then sold for a little money and “some free beer” to Ronald Guest, the landlord of a local pub.

Then, in late September, the landlord’s family, living in the town of Hastings, in southeast England, reached out to McCartney’s studio: Could the guitar in their loft be the missing bass?

‘It’s Hardly Traveled Any Distance at All’

“We thought this bass would have gone off on a more glitzy journey,” said Jones, adding that in fact, the research indicated that the guitar had stayed in the same family. “In all of those years, it’s hardly traveled any distance at all.”

Jones said that a member of the Guest family handed the guitar over to McCartney’s studio in Sussex, England.

Posts on social media appeared to show Ruaidhri Guest, 21, holding the guitar. He did not immediately respond to a request for comment, but he said in a post Friday that the family would be releasing details “in due course.”

Soon after the guitar emerged in late September, Wass drove from Germany to England to help authenticate that it was, in fact, that Höfner.

“There it was in my hands,” Wass said, adding that he had been looking for the guitar since McCartney inquired about it several years ago. Finding it, he said, felt “thrilling.”

“It didn’t take me more than 10 seconds to know it was the right one,” he said. Wass pointed to the left-handed guitar’s distinctive parts and color.

The guitar had sustained some damage, he said, including a cracked neck, and would need to be repaired.

Its discovery stunned even its searchers, who said they were hopeful but realistic about their prospects as they pieced together the clues from archival clippings and tips. “We never assumed that we’d find it,” Jones said. “If we had to be honest, the chances were probably very, very slim.”

Other famous lost instruments have also been unearthed: A Gibson acoustic guitar belonging to John Lennon that had been lost for decades turned up and was sold for $2.4 million to an anonymous buyer in 2015.

Despite the odds, the team said they were driven by a determination to preserve a piece of Beatles mythology.

“All the Beatles fans everywhere can see this bass again,” said Wass. “I’m hoping Paul McCartney, when he gets it back, will play it for us all.”

This article originally appeared in The New York Times.