The National Trust's libraries include just over 100 incunabula (books printed before 1501).

Hundreds more were sold in the late 19th and early 20th centuries.

The first book printed in Europe with moveable type was the Gutenberg Bible, printed in Mainz in 1454-1455. There was one in the library at Sudbury Hall in the 19th century.

The first English printer was William Caxton. None of his books are found in National Trust libraries, but there are two by his successor Wynkyn de Worde, and a set of fragments by the first Oxford printer, Theodoric Rood.

Like manuscripts, the incunables generally fall into two categories: books which have been in houses for hundreds of years, and others - the majority - collected by connoisseurs in the 18th and 19th centuries.

The first category contains the 28 incunables at Lanhydrock in Cornwall, part of the working library of the Oxford scholar Hanibal Gamon (c. 1582 - 1651), who moved to Cornwall in 1619.

The second includes books at Hughenden Manor, Kedleston Hall, Wimpole Hall - and above all the 68 incunables from the library of Sir Richard Ellys (1674 - 1742) at Blickling Hall, including first editions of many of the great classical texts, usually in magnificent copies of distinguished provenance.