Huygens' inscription indicates that he thought that de Bisschop made this drawing after a painting by Hans Holbein the Younger. However, this drawing probably copies a painting by Joos van Cleve (circa 1485-1540), formerly in the Watney Collection, Cornbury Park, Oxon., sold at Christie's, London, 23 June 1967, lot 41 (Fig. 1).
Fig. 1. Joos van Cleve, Portrait of a Gentleman, oil on panel, 50.8 x 43.20 cm., present whereabouts unknown.