An anonymous portrait of Shakespeare's leading actor, Richard Burbage, at the Dulwich Picture Gallery

Beyond its serious, thoughtfull expression, it may be uncertain to specify what this portrait contributes to our understanding of Burbage's performances in major Shakespearean roles such as Richard III, Hamlet, Lear, etc., but at least we know what Shakespeare's principal performer looked like. Courtesy of the Yorck Project, under Creative Commons Attribution-Share-Alike License.