Volunteers write and edit the site's thousands of articles

The editor, known as Essjay, had described himself as a professor of religion at a private university.

But he was in fact Ryan Jordan, 24, a college student from Kentucky who used texts such as Catholicism for Dummies. He has now retired from the site.

Wikipedia is an encyclopaedia open to all, written by volunteers worldwide.

'Trust and tolerance'

Under the name Essjay, Mr Jordan edited articles and also had the authority to arbitrate disputes between authors.

In his user profile, he said he taught both undergraduate and graduate theology, and in an interview with the New Yorker in July 2006, was described as a "tenured professor of religion".

His real identity came to light last week when the magazine added an editorial note to the piece highlighting the deception.

"At the time of publication, neither we nor Wikipedia knew Essjay's real name," the note said.

Essjay told them he hid his identity because "he feared personal retribution from those he had ruled against online", the magazine's note said.

Wikipedia co-founder Jimmy Wales, writing on the site on 3 March, said that Mr Jordan was apologetic, but that Wikipedia was "based on twin pillars of trust and tolerance".

"Despite my personal forgiveness, I hope that he will accept my resignation request, because forgiveness or not, these positions are not appropriate for him now," he wrote.

And in a post the next day, Mr Jordan announced his retirement from the site.

"I hope others will refocus the energy they have spent the past few days in defending and denouncing me to make something here at Wikipedia better," he said.