Oil sketches, also known as oil studies, were first produced by early European artists as a method of providing a preview of a finished painting to their commissioner, though by the 17th century they were appreciated as complete works in themselves.
Rubens was very fond of this style, and is one of the most famous artists to use it. The French art critic Roger de Piles visited Rubens on occasion, and remarked on how Rubens oil sketches can have greater appeal to the sophisticated viewer than some of his more finished paintings. He describes how the organic, sometimes unfinished, composition of an oil sketch can create a more intimate connection with its viewer. Unlike a highly finished painting which leave little to the imagination, with an oil sketch the mind of the viewer interacts with the painting and not so much completes it, but becomes part of it, giving oil sketches a personal and dynamic feel.