Tragedy masks on a Roman pillar from the second century AD. Comedy masks appear on the opposite side of the carving.
Praefcke, A. (2010, October) Doppelseitiges Maskenrelief. [Photograph]. Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Doppelseitiges_Maskenrelief_KHM_I_119_1.jpg
National Theatre. (2013, January 12). An Introduction to Greek Tragedy [Video]. YouTube. https://www.youtube.com/watch?v=dSr6mP-zxUc
National Theatre. (2013, March 27). An Introduction to Greek Comedy and Satyr Drama [Video]. YouTube. https://www.youtube.com/watch?v=H-BvMbfkxcc