# What a Sleeper Is, and Why They Still Happen > A GBP 524.80 picture catalogued as a follower of Ibbetson turned out to be Turner's first exhibited oil. The finder's edge is time, and the English courts have said so. > The Study - 2026-08-02 > Canonical HTML: https://iconotheca.com/study/what-is-a-sleeper/ ## Key points - The Turner was catalogued at Dreweatts as a follower of Julius Caesar Ibbetson and cost GBP 524.80 with fees; fifteen months later it hammered at GBP 1.5 million. - An Artemisia Gentileschi bought at Hampel in Munich for EUR 104,000 in 2018 sold at Sotheby's for GBP 1.6 million hammer in 2025. - In Thwaytes v Sotheby's the High Court held the house had no obligation to run infrared analysis on a lot catalogued as a follower. - Around thirty other versions of Caravaggio's Cardsharps were offered at auction between 1988 and 2012, two of them during the trial itself. ## The definition, and who profits from it ## Why they still exist ## The Turner, with the record corrected ## Four more, with the figures attached ## What the finder risks, and what the courts have held ## The side of the transaction nobody prints A sleeper is not a miracle. It is a picture nobody had time to look at properly, bought by somebody who did, and the English courts have held that the house owed no more than the care its specialists actually took. What separated the buyer of a GBP 524.80 Ibbetson from everyone else at Donnington Priory in April 2024 was not luck. It was knowing enough to hold a better wrong answer than the catalogue's, and then paying for the cleaning that turned it into a right one. ## Questions **Is buying a sleeper unethical?** Not in itself, and English law has declined to unwind such a sale. The buyer takes a real risk on an opinion nobody else holds and funds the research that may destroy it. The contested question is distributional rather than legal, and it concerns what the original owner receives. **Can a seller sue to reverse a sleeper sale?** In England the leading attempt failed: Thwaytes v Sotheby's, dismissed in January 2015, held the house was entitled to rely on its specialists and had no duty to commission infrared analysis. French law has been more receptive, with the Cour de cassation in 1983 admitting evidence produced after the contract to establish a mistake. **Where do sleepers appear?** Regional and provincial salerooms, house clearances, barn and attic finds, and small local houses. The Turner came from Newbury, the Gentileschi from Munich, the Cimabue from a house clearance near Compiegne, the Frans Post from a barn attic and the Salvator Mundi from a New Orleans estate sale. **How often do they turn out to be nothing?** No published figure exists, and anyone quoting a rate is estimating. What is documented is that dealers describe the model as requiring many small bets and the discipline to write off failures, and that individual gambles run to seven figures before any confirmation exists. ## Sources - [1] James Marrone and Silvia Beltrametti, 'Sleeper Antiquities: Misattributions in Sales of Ancient Art', International Journal of Cultural Property vol. 27 no. 1, February 2020. - [2] Ben Lewis, 'It's time to end the predatory practices of sleeper hunters', The Art Newspaper, 14 March 2024. - [3] Sallie Brady, 'Finders, Sleepers', Art and Antiques Magazine, 1 July 2010, with Ian Butchoff and Philip Mould. - [4] Gareth Harris, 'Newly attributed Turner painting previously sold for 500 pounds goes under the hammer at Sotheby's', The Art Newspaper, 9 June 2025, giving the Dreweatts attribution to a follower of Ibbetson and the GBP 524.80 figure. - [5] Anna Brady, 'Turner painting bought last year for 500 pounds sells for almost 2m pounds at Sotheby's', The Art Newspaper, 4 July 2025, giving the GBP 1.5m hammer and the Gentileschi figures. - [6] Sotheby's, lot page for The Rising Squall, Old Master and 19th Century Paintings Evening Auction L25033, 2 July 2025, with the Dreweatts provenance line. - [7] Anna Brady, 'Kitchen Cimabue sells for 24.1m euros', The Art Newspaper, 27 October 2019. - [8] Julie Belcove, 'Frans Post Painting Found in a Barn, Sold for Over $7 Million', ARTnews, 29 May 2025, with George Wachter and Nancy Krieg. - [9] Dianne Dwyer Modestini, 'History of the Salvator Mundi', Salvator Mundi Revisited, giving the St Charles Gallery lot description and the USD 750 estate appraisal. - [10] St Charles Gallery, New Orleans, Prices Realized sheet for the April 2005 sale, listing lot 664 at an aggregate of 1,175. - [11] Thwaytes v Sotheby's [2015] EWHC 36 (Ch), Mrs Justice Rose, 16 January 2015, full judgment. - [12] Cour de cassation, first civil chamber, 13 December 1983, Saint-Arroman, English translation published by the University of Texas School of Law, Foreign Law Translations.