A working manuscript of one of Beethoven's final compositions has been rediscovered in a seminary library and could fetch more than $2 million at auction.

The 80-page manuscript of Beethoven's "Grosse Fuge" for piano duet was created when he was deaf and is filled with editing and notations from the composer's own hand. Never before seen by scholars, it was written a few months before the composer's death in 1827.

It was found by a librarian clearing out old archives at the Palmer Theological Seminary and was displayed briefly at the seminary Thursday in a glass case and under the eyes of several plainclothes guards.

The discovery, first reported Thursday by the New York Times, had been kept hidden since July while the bound manuscript, roughly the size of a magazine, was authenticated and appraised.

"That has been the toughest part -- keeping this all a secret till now," seminary president Wallace Smith said.

Longtime librarian Heather Carbo, who school officials said did not wish to speak with reporters Thursday, found the manuscript on the bottom shelf of an old cabinet. Months earlier, an electrical fire had damaged many items in the library archives, but the manuscript was unharmed.

University of Pennsylvania musicologist Jeffrey Kallberg, who authenticated the manuscript, said its condition was pristine because it has not been touched or moved for so many decades.

"It's a very important discovery," he said. "This was a controversial and not understood work because it was so ahead of its time. It sounds like it was written by a dissonant 20th-century composer."

The manuscript was last mentioned in an 1890 auction catalogue from Berlin. No documents were ever located to indicate who had purchased it then, but seminary officials now believe that the buyer was industrialist and hymn composer William Howard Doane.

His daughter, Marguerite Treat Doane, donated a collection of documents to the seminary in 1950, among them musical manuscripts that likely included the Beethoven, to pay for construction of a chapel.

Somewhere along the way, it was forgotten.

"In all the Beethoven literature, it's described as lost," said Stephen Roe, a Sotheby's expert in charge of the Dec. 1 sale. "There are lots of alterations, changes, revisions that no one has ever seen."

Sotheby's estimates that the find could bring as much as $2.6 million at the auction in London.

The proceeds from the sale of what Smith called the "Beethoven blessing" will be used to pay debts, build up the scholarship program and expand initiatives including a training program in West Virginia, Smith said.