Police are quizzing a man over the theft of a rare collection of works by William Shakespeare stolen from Durham University 10 years ago.
The first folio edition of the Shakespeare works, published in 1623 and said by police to be worth 15 million pounds, was among items taken during a break-in at the university library in December 1998.
Thieves had forced open glass-top display cases during an exhibition of English literature dating back to the Middle Ages.
There was no news of the books and documents taken until police were alerted two weeks ago by the British Embassy in the United States.
A man who said he was an international businessman had visited a respected library in Washington to ask staff to verify whether a book he had bought in Cuba was genuine.
He agreed to leave it with the library for a search to be carried out. But checks revealed it to be the one stolen from Durham and staff called in the authorities.
British police said they had worked with the U.S. Federal Bureau of Investigation and worldwide inquiries were launched to trace the man.
That culminated in the arrest on Thursday of a 51-year-old man in Washington, Tyne and Wear, near Durham.
"The Shakespeare folio currently remains in the safe care of the Washington library (in the United States)," said Detective Superintendent Andy Reddick of Durham Police.
Other items taken in the raid included a 14th or 15th century manuscript of an English translation of the New Testament and a handwritten manuscript from the same period of a fragment of a poem by Geoffrey Chaucer.
Police said the documents would have been impossible to sell legitimately.