LONDON (AP) — Eleanor Rigby: fact or fiction?

That question, which has bedeviled Beatles' fans for decades, may be answered in part by a 1911 hospital payroll sheet to be auctioned in London tomorrow.

The document, sent by Paul McCartney in 1990 to the director of a music charity who had asked for funding, contains the signature of a maid named "E. Rigby" who worked in a Liverpool hospital.

Ted Owen, director of the company auctioning the document, believes the woman who signed the sheet is the "Eleanor Rigby" buried in 1939 in a Liverpool graveyard next to the church where McCartney met the young John Lennon.

"I've spoken to the person who lived in the house where she used to live, and they've confirmed that the signature is the same signature of the person in the graveyard," he said, adding that the finding may contradict McCartney's longtime assertion that the song was based on a made-up character.

"It's intriguing that McCartney owned it because he says he created the song around a fictitious figure," said Owen. "And yet, how did he have this document and why did he have it? When he was asked to donate money, he sent this."

McCartney has said the song was not based on a real person but has said he may have been subconsciously influenced by having seen the tombstone.

When the auction by the Fame Bureau was announced, he released a statement reiterating that the character was not real.

"If someone wants to spend money buying a document to prove that a fictitious character exists, that's fine with me," he said.

The payroll sheet was signed by "E. Rigby" after she collected her pay at Liverpool's City Hospital. McCartney has not revealed how he got the document, or why he sent it to the charity 18 years ago.

The song, released in 1966 as a single and on the Beatles' Revolver album, represented a sharp break for the band, which until then had largely relied on happy, cheerful tunes for their international hits. With its haunting refrain, "Ah, look at all the lonely people" it is a devastating portrayal of an isolated woman whose death draws so little notice that no one attends her funeral.

There are no rock and roll guitars or drums on the sombre track — McCartney's lead vocal is backed by violins, violas and cellos arranged by Beatles producer George Martin.

"It's a Beatles song with no Beatles instruments," said Glenn Gass, a rock historian who teaches a course on the Beatles at Indiana University.

"It's just so bleak and so sad: she picks up the rice at someone else's wedding, the whole image of her wearing a face that she keeps in a jar by the door. There are things happening emotionally that you just can't see. It's not a pop song in any traditional sense, but it's one of their great songs."

Lennon and George Harrison sing harmony; Ringo Starr does not play or sing, although Beatles experts say he contributed one line to the lyrics. "Eleanor Rigby" is credited to the Lennon-McCartney writing team, but it is widely regarded as primarily by McCartney.

McCartney has said he considered naming the woman in the song "Daisy Hawkins." He also mulled naming the unsympathetic priest "Father McCartney" but decided on "Father McKenzie" so his own father wouldn't be burdened.

The song has had so much impact that a statue honoring Eleanor Rigby — be she real or imagined — has been built in downtown Liverpool. Passersby often place flowers there in the summer months.

Interest is so high it is estimated that the document may fetch £500,000 ($750,000) at the auction.

Owen said "every penny" will go to Sunbeams Music Trust, a charity that provides music instruction to people with special needs.

The charity's founder, Annie Mawson, received the document from McCartney after writing him an 11-page letter seeking help for her foundation, which uses Beatles songs, among others, to teach music to people with physical and mental challenges. She has found, for example, that autistic children respond well to Beatles music.

"I told Paul McCartney how his music had helped so many vulnerable children," she said.

She hand delivered the letter to McCartney's London office in 1989 and got the hospital document in the mail the following year. It was in an envelope carrying the logo of McCartney's world tour, but did not contain any note.

"I think my letter moved him so he sent me this beautiful parchment document, a ledger, from 1911, showing E. Rigby," Mawson said. "My head was whirling when I saw the significance."

Her plan is to use the proceeds from the auction to finally build a music instruction centre in Cumbria, England, where the charity is based.

"This is what I dreamt about in the '90s," she said, explaining that she held the document for years as the value of Beatles memorabilia soared.

"It's taken this long to develop the charity and get a good team behind it and now we really need a proper centre."