Two Deformed Heads by Wenceslaus Hollar, etching, circa 1625-77. In his Trattato, Leonardo da Vinci argues that certain attributes of the face may in fact be physical apparitions of the inner self, but are not the sole window to the essence of man. The etchings after Leonardo of grotesque heads by Wenceslaus Hollar clearly depict this kind of amazement at the possibility that character of a person can be mirrored by his outer appearance. Such "grotesque" or "bizarre" images, simultaneously horrible and marvelous, have influenced portraiture and caricature ever since their origin in the Italian Renaissance. The depiction of the abnormal in Renaissance art became increasingly popular in this period, developing as an artistic genre in its own right. The first to print these caricatures of Leonardo, twenty-six etchings in all, Hollar helped perpetuate the Renaissance love of anything strange and uncommon in art and literature.