All early references to this fascinating panel attribute it to Van Dyck, though in fact it must come from Rubens’s studio during an earlier period (c. 1610-5). It has the technique of a Rubens oil sketch and shows three positions of horse and rider which appear often in Rubens’s work, yet it is not good enough to be by Rubens himself. The most likely explanation is that it is the result of a training exercise c. 1610-5 during which a pupil in Rubens’s studio copied a now lost oil sketch by the master. This lost oil sketch is probably the basis for the large scale painting, also probably from Rubens’s studio (formerly in the Kaiser Friedrich Museum, Berlin).