In his Schilderboeck published in 1604, Karel van Mander relates that his friend, Cornelis Ketel "got the urge to paint without brushes, with his hands" and that a year later, in 1600, "it occurred to him to paint without hands, with his feet". This astonishing artistic process has aroused the curiosity of many amateurs and art historians since the seventeenth century, but the reasons that led van Mander to name the technical eccentricities of this painter-poet were never convincingly explained. The present article aims at understanding these singular acts and their underlining in the context of the artists' lives and the artistic theory of this period.