A pristine set of Goya’s famous bullfighting etchings, valued at up to £500,000, has been discovered in an old ledger in the library of a French chateau.

The library was full of handsomely bound volumes, but at the back of one shelf the owners found a drab ledger, holding a rather dull series of 90 French military prints – and a few pages further on, a complete pristine set of the first edition of Goya’s La Tauromaquia etchings, apparently forgotten about for more than 150 years.

Severine Nackers, head of prints at Sotheby’s in London, where the set will be sold in April, described the prints, still in the 19th-century ledger ruled for columns of accounts, as “a once in a lifetime discovery”.

The prints were found by the present owners of Château de Montigny, in Eure-et-Loir, northern France, as they went through all the books in their library, probably the first full audit in many generations. In the 1830s their ancestor the Marquis de Laval, once a political refugee to England after the French Revolution, had to build an extension to hold the collection he amassed in his successful career as a politician and diplomat after the monarchy was restored.



Many copies of the first edition of prints are in libraries and museums. Photograph: WestImage - Art Digital Studio/Sothebys

The prints are being sold, Nackers said, “because like most owners of a French chateau, they need to invest in the building”.

The Spanish artist, who was fascinated by the bullring and once painted himself wearing the ornate embroidered jacket of a matador, created the set of 33 images in 1815-16, while also working on his harrowing series Disasters of War. Unlike the dangerously political war images, Goya had some hope of making money out of the popular and safe subject of bullfighting.



Even in his day complete sets were rare, as they were also sold as separate prints. Many copies of the first edition, printed for the artist from copper plates he etched himself, are now in libraries and museums. Although at the time they did not make the fortune he hoped for, today they are coveted by collectors. The world record for Goya prints was set in New York four years ago, when a set of La Tauromaquia sold for $1.9m.

The marquis acquired his set in Madrid soon after they were published, possibly as a diplomatic gift. The fortunes of Anne-Adrien-Pierre de Montmorency-Laval, who inherited the more manageable family ducal title, had soared with the abdication of Napoleon and the restoration of the Bourbon kings, Louis XVIII in France and Ferdinand VII in Spain. He was ambassador to Madrid from 1814 to 1823, and went on to other posts in Rome, Vienna and London, before retiring to the magnificent chateau he had inherited.



The etchings had been carefully mounted in the ledger using a dot of glue in each corner. Photograph: WestImage - Art Digital Studio/Sothebys

He died in 1837, and his many properties and titles were inherited by his daughter and her husband: it is their title and Paris address on the ledger, which may have been chosen to hold the prints temporarily because it fitted the uncut sheets so well. They were carefully mounted, with a dot of glue in each corner, and despite being inserted face to face rather than interleaved, have survived in immaculate condition.

They will be sold in Sotheby’s prints and multiples auction in London on 4 April.