"A rare example of an oil sketch by Reynolds, this is likely to be a preparatory work for a portrait of Lord Ligonier (1680-1770), finished versions of which are now held at Fort Ligonier in Pennsylvania and at Tate Britain. In the cloud of smoke rising above the rearing horse the features of a woman can just be discerned, indicating that Reynolds had used this canvas to paint a portrait before recycling it for this sketch.
This work has been hung in the same room as the equestrian portrait of the Infante Balthasar Carlos by the studio of Velázquez, which Reynolds is likely to have admired when it was in the collection of the Gallery's founders."