It’s the kind of find every librarian (and indeed book collector) dreams of. While cataloging in the University of Reading’s archives, special collections librarian Erika Delbecque came across a buried treasure. Riffling through a collection purchased by the library in 1997 from the late typographer John Lewis for £70,000, she managed to identify two pages, among thousands of items, as being unique.

Rachel Revesz of the Independent reports that Delbecque “instantly noticed the ‘trademark blackletter typeface’, the layout and red paragraph marks, which were typically added by hand after printing and which indicated the pages were an example of very early printing in Western Europe.”

The pages come from a medieval priest’s handbook—some of the first printing ever done in England—made by William Caxton sometime between 1467 and 1477. Caxton set up his own press in London in late 1475 or early 1476, seeing commercial potential in the new technology, and is usually considered to have been Britain’s first printer and book retailer.

“This well preserved item is the only one of its kind, and one of just two surviving fragments from this mediaeval Caxton book in existence,” Delbecque said. “The leaf had previously been pasted into another book for the undignified purpose of reinforcing its spine. We understand it was rescued by a librarian at the University of Cambridge in 1820, who had no idea that it was an original Caxton leaf.”

William Caxton’s insignia, US Library of Congress. Via Wikimedia Commons.

The book, entitled Sarum Ordinal or Sarum Pye, was produced before the reformation with the aim of guiding priests through English saints’ feast days. The original book would have been 160 pages long, and the manuscript was created for the Bishop of Salisbury.

The only other surviving fragments ever discovered are held at the British Library in London, who have eight double-sided pages of the book. There are believed to be only a further seventy-nine surviving examples of texts printed in England in 1476 and 1477.

Dr. Lotte Hellinga, a former deputy keeper at the British Library and a Caxton expert, was quoted by the Independent’s Rozina Sabur as saying:

“It is very rare that an unknown piece of printing by William Caxton is brought to light. The example found in Reading belongs to a different part of the book than those held in the British Library.

“Its condition is good, considering it spent some 300 years bound in the spine of a book and another 200 resting forgotten in an album of fragments rescued from other bindings.”

Early printing specialist Andrew Hunter of Blackwells Books evaluated the find, estimating the two pages to be worth £100,000, and adding that “the discovery of even a fragment from among Caxton’s earliest printing in England is thrilling to bibliophiles, and of great interest to scholars.”

“If this were ever to come on the market,” he added, “there would definitely be competition for it. It would be a great prize for a private collector, and a feather in the cap of any institution.”

For now the pages will go on display at the university’s Museum of English Rural Life from May 9 to May 30, the first time the public will have seen them since the fifteenth century.