If a prize were to be awarded for the biggest surprise at Maastricht, it might go to the Jan Steen brought by Simon Dickinson and James Roundell. The Dutch artist is renowned for his interior scenes, mostly smoky taverns with rough-looking drinkers and lewd women,  painted in a small format. The last thing connoisseurs expect from him is a large picture with a mythological subject. Dickinson and Roundell’s Steen, The Sacrifice of Iphigenia, measuring 53 by 68 inches, was done in a thoroughly Italianate style utterly unlike the artist’s usual grim realism. Yet no shadow of a doubt hangs over the painting, which is signed and dated 1671. It was displayed at the Rijksmuseum, in Amsterdam, for more than four decades before being returned, in 2006, to the heirs of the famous Jewish collector-dealer Jacques Goudstikker. Although the picture is well known to art historians, it did not receive remotely as much attention in the rich surroundings of one of the two greatest museums of Dutch painting (the other being the Mauritshuis, in The Hague) as it did at Maastricht. At €8 million ($12.4 million), the painting was quickly sold.

Some of the previously unknown works displayed at Maastricht came with remarkable stories that have remained unpublicized. One such tale attaches to the small interior scene by Adriaen Brouwer shown by Bruce Livie, the Munich-based American dealer who runs the Arnoldi-Livie Gallery in partnership with his wife, Angelika Arnoldi-Livie. The Flemish Brouwer, who died in 1638, belonged to the first generation to produce such paintings. In Livie’s small panel, an elderly man has fallen asleep in his chair while a coarse-looking character dallies with a tavern wench in the background, spied upon by a voyeur grinning down at them through an opening in the wall.

The panel came to the Munich dealer by a circuitous route. It first surfaced in a small sale in Brussels, to which it was reportedly consigned by the Bergeyck family after being rejected by a major auction-house specialist as the anonymous work of a minor artist. A professional with a sharp eye bought the scene and took it to Sotheby’s in Amsterdam, where it was recognized as a Brouwer and put up for sale as such. The painting had, however, been tainted by its earlier tribulations, which were known to several professionals, and Livie faced only mild competition when he bid for it.

Having bought it, the dealer set about researching his Brouwer. A critical clue was an early 20th-century label on the panel’s back identifying the then owner as a count de Bergeyck. A search through early sources revealed that in the 17th century, a de Bergeyck had been the second husband of the widow of Peter Paul Rubens, Hélène Fourment, who had inherited all the famous Flemish master’s art holdings. Rubens, who doubled as a dealer and art broker, owned 13 Brouwers when he died. It became clear to Livie that his acquisition was almost certainly one of these. The last step in his sleuthing endeavor was to submit the panel to the most accomplished expert on Brouwer: Konrad Renger, who had recently retired as curator of Dutch and Flemish paintings at the Alte Pinakothek, in Munich, where he had organized a great retrospective of the artist in 1986. Renger confirmed the authenticity of Livie’s picture.

As is often the case with paintings that have stayed in the same family for centuries, the panel is superbly preserved. On March 7 at TEFAF, the curator of a European museum pounced on the €750,000 ($1.2 million) picture, made doubly important by its historic provenance.

Museums generally take much longer to reach a decision on purchases. The sales of two pictures were being negotiated as the fair ended.

One of these, brought by the New York Old Masters dealer Richard Feigen, illustrates the role chance plays in art-historical scoops. Feigen told me that he had walked into the Hôtel Drouot, the Paris auction house, and come across a Neoclassical painting covered in grime. He had not been aware that the picture was being sold that week, nor had he read the catalogue entry for it. The signature of François-André Vincent and the date 1784 were both visible on the large canvas, and the dealer bought it. Back home, he embarked on some digging. His researcher, Ann Guité, found a description of the painting in the brochure of the 1785 Paris Salon, accompanied by an engraved reproduction. French Neoclassicism has been exciting art historians for a good decade. As TEFAF closed, four museums were expressing interest in the Vincent, with its €550,000  ($849,200) price tag.