Grosvenor and Dabiri travel to Devon to investigate a small portrait of Rembrandt in the collection of a National Trust house, Knightshayes Court. The painting is thought to be a later copy of a Rembrandt self-portrait, but Bendor believes it is actually a study for the finished picture, made by Rembrandt himself.

At the Manchester Art Gallery, Grosvenor finds a painting of a country gentleman from the 1770s that he believes has been misattributed to Nathaniel Dance. He feels certain that it is the work of German painter Johann Zoffany, a favorite portraitist of the royal family under King George III.

Petworth House in West Sussex, one of the great baroque treasure houses of England, yields two paintings warranting investigation: a portrait once attributed to Rubens that Grosvenor thinks is by Anthony Van Dyck, and a portrait of a young cardinal “in the style of” Titian, which he believes may be by Titian himself.

Hanging in a reading room at Oxford University’s Bodleian Library is a portrait of a fellow of Merton College, George Oakley Aldrich, by an unknown artist. Bendor suspects it may have been painted in Rome in the 1750s by the master of Grand Tour portraits, Pompeo Batoni.

In Birmingham Museum and Art Gallery, a roughly painted woodland scene is catalogued as “After” Thomas Gainsborough, but there is evidence it may be a preparatory sketch for the painter’s last great landscape, one of his picturesque “Cottage Door” series.

In the stores of the National Museum of Wales in Cardiff is a Madonna and Child by a follower of Botticelli, the early Renaissance painter of that most iconic painting, “The Birth of Venus.” Could it in fact be from the hand of the master himself?