1) Make-up 2) Theatre character 3) They performed in blackface 4) War paint 
Blackface is a form of theatrical makeup used by performers to represent a black person. The practice gained popularity during the 19th century and contributed to the proliferation of stereotypes such as the `happy-go-lucky darky on the plantation` or the `dandified coon`. In 1848, blackface minstrel shows were an American national art of the ...
(from the article `minstrel show`) indigenous American theatrical form comprising a group of blackfaced white minstrels whose material caricatured the singing and dancing of slaves. It ...
[n] - the makeup (usually burnt cork) used by a performer in order to imitate a Negro
A particularly stupid variety of sheep with a rough long fleece and relatively light body weight but very hardy. 
noun the makeup (usually burnt cork) used by a performer in order to imitate a Negro
They performed in blackface. · an entertainer, esp. one in a minstrel show, made up in the role of a black. · the makeup, as burnt cork, used in this role:They performed in blackface.