A unique example of 15th century printed text by English printer William Caxton has been unearthed at the University of Reading.
The two pages are from a medieval priest handbook dating back to late 1476 or early 1477, which was among the first books printed in England by William Caxton's pioneering press.
No other copies of the pages, printed either side of a single leaf of paper, are known to have survived.
It was found in the University's archives by Erika Delbecque, Special Collections librarian, while she was cataloguing thousands of items illustrating the history of printing and graphic design. The find is said to be worth up to £100,000. The surprise has gone on public display in the University's Special Collections department.
Early printing specialist Andrew Hunter, of Blackwells Books, who carried out the valuation of the leaf, said: "In the world of rare books, certain words have special, almost magic, resonance, and Caxton is one of them. Thus 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 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."