Gustave Doré (1832–1883), The Enigma (souvenirs de 1870) (1871), oil on canvas, 128 x 194 cm, Musée d’Orsay, Paris.

Not long after the end of the Franco-Prussian War, in which he had served in the National Guard, Gustave Doré committed some of the apocalytic visions of the siege of Paris to canvas, in his The Enigma (souvenirs de 1870), and two other major paintings, all made using grisaille, the greys normally used to model tones in traditional layered technique.