Sketch reproducing an ancient Roman graffito of a gladiator, originally from Pompeii.
When I went to Capua in 2004, the Gladiator Museum had an exhibit of replica gladiator graffiti, originally found on the podium of a tomb in the necropolis outside the Nucerian Gate of Pompeii. Many of the graffiti show drawings of gladiators.
Another Flickr user identified this type of gladiator as a Thraex = Thracian.
(original photo by me)