An academic who discovered a lost JRR Tolkien manuscript had to contend with obsessive fans and "strange" lingering resentments to get it published, he has said.

Professor Michael Drout came across Tolkien's translation of eighth century epic Beowulf in an Oxford University library six years ago.

The Lord of the Rings author had written the 2,000-page translation and appraisal, called Beowulf, the Monsters and the Critics, for a British Academy lecture in 1936.

It has been the most joyful and fulfilling experience I've had in academia, but the learning curve was very, very steep Professor Michael Drout

It has now been published in the United States - but only after an epic struggle against the fears of Tolkien's estate that the author's legacy might be exploited, and the intrusion of some fans.

"I now know more than I ever wanted to about the difficulties of editing a 20th Century manuscript, about copyright regulations, about the strange personal and academic resentments that still lurk in various quarters nearly 30 years after Tolkien's death," Prof Drout said.

"Taken all together, it has been the most joyful and fulfilling experience I've had in academia, but the learning curve was very, very steep."

It was unfortunate that there were some obsessive fans who "whose attention one attracts by working on anything related to Tolkien", he added.

The late author's estate was initially reluctant to give permission for Prof Drout to publish the translation because so many people try to exploit Tolkien's legacy.

The estate has turned down ideas for everything from Tolkien coffins to Hobbit slippers, Prof Drout said.

Bilbo Baggins celebrated his 111th birthday in Lord of the Rings

"The sheer number of people who were trying to profit from Tolkien's work was astonishing, and the problems with copyright violation and outright theft were like nothing I had ever encountered in medieval studies," he said.

Tolkien's original lecture is credited with changing the tide of opinion from looking at Beowulf as bad history to great poetry.

Prof Drout also said The Lord of the Rings was heavily influenced by the Old English classic, with orcs, elves and a talking tree all borrowed from the Anglo Saxon story.

On Friday, some of the author's biggest fans were celebrating Tolkien's 111th - or "eleventy-first" - birthday.

It is the age that hobbit Bilbo Baggins celebrated at the start of The Lord of the Rings, and was described in the book as "a rather curious number and a very respectable age for a hobbit".

The Tolkien Society encouraged fans to drink a toast to the writer at 2100 GMT, and is producing a DVD of fans celebrating around the world.