Disguised portraiture was frequently used by fashionable portraitists like Drouais and allowed sitters to convey added layers of information through reference to myth and ancient history. “Vestal Virgin” comes from a category of women in ancient Rome who devoted themselves to Vesta, goddess of the hearth (alluded to here in the brazier on which offerings might be made). This guise was well-suited to women who were unmarried or about to marry. This unknown sitter’s gold-trimmed robe is not contemporary dress but a historicizing costume; her pose, unveiling herself, is typical of the simultaneously chaste and alluring nature of this particular disguise.

百度翻译：http://fanyi.baidu.com

　　维斯塔贞女或称护火贞女，是古罗马炉灶和家庭女神维斯塔的女祭司。 维斯塔贞女的祭司职位是由六位女祭司组成，其年龄介于六至十岁间，必须守贞、侍奉神祇至少三十年。她们的主要任务是守护维斯塔神庙的炉灶，不让圣火浇熄，并以宁芙埃格里娅的圣春之水涤洗神庙。