According to Schwarzmaier (pp. 42-45 in Hart, et al., The Art of Ancient Greek Theater) masks were adopted in ancient Greek theater to disguise the male actors, who would often play multiple roles and both genders. The mask allowed for a quicker costume change than face paint, which, as literary tradition explains, was how Thespis (the inventor of Attic tragedy) disguised his protagonists in the 6th century B.C. These masks "did not register fleeting emotions; rather, they conveyed the figure's essential nature, his or her unchanging character and social status (p. 44, op. cit.)." In Comedy, masks were designated for a set of characters; slaves were one popular subject. Common characteristics were a megaphone mouth and a speira, a hairstyle with a roll of hair framing the face and hanging down at the sides, as visible here. These dynamic figures were often featured as decorative schemes for home and garden furnishings. For a Roman bronze incense burner in the form of an actor seated on an altar, wearing a similar mask of a comic slave, see no. 87, op. cit.