Madame Moitessier, 1856 by Jacques-Auguste-Dominque Ingres, National Gallery of Art, London.
True to the fashion of his time, Ingres was more interested in painting historic scenes than doing portraits, but also true, portraits are an artist's bread and butter. Mme. Moitessier's husband asked Ingres to paint his wife's portrait and Ingres refused, upon meeting her however, he was intrigued and agreed to paint her. Notice how the use of the mirror behind her, gives us two portraits in one.